Final Draft
GUIDE FOR INSPECTING
CAPTURE SYSTEMS AND
CONTROL DEVICES AT
SURFACE COATING
OPERATIONS
Office of Air, Noise and Radiation Enforcement
Division of Stationary Source Enforcement
Washington, D.C. 20460
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GCA-TR-82-38-G
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Division of Stationary Source Enforcement
Washington, DC 20460
Contract No. 68-01-6316
Technical Service Area 1
Task Order No. 33
GUIDE FOR INSPECTING CAPTURE
SYSTEMS AND CONTROL DEVICES AT
SURFACE COATING OPERATIONS
Draft Final Report
May 1982
Prepared by
Robert G. Mclnnes
Brian R. Hobbs
Stephen V. Capone
GCA CORPORATION
GCA/TECHNOLOGY DIVISION
Bedford, Massachusetts
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DISCLAIMER
This Draft Final Report was furnished to the Environmental Protection
Agency by the GCA Corporation, GCA/Technology Division, Bedford, Massachusetts
01730, in fulfillment of Contract No. 68-01-6316, Technical Service Area
No. 1, Task Order 33. The opinions, findings, and conclusions expressed are
those of the authors and not necessarily those of the Environmental Protection
Agency or the cooperating agencies. Mention of company or product names is
not to be considered as an endorsement by the Environmental Protection Agency.
This document has not been peer and administratively reviewed within EPA
and is for internal Agency use/distribution only.
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CONTENTS
Figures iv
Tables v
1.0 Introduction 1
1.1 Purpose and Use of this Guide 1
1.2 Organizatin of this Guide 2
1.3 Surface Coating Industries 3
2.0 Surface Coating Operations 8
2.1 Surface Preparation 8
2.2 Coating Preparation 8
2.3 Types of Coatings 9
2.4 Coating Application 9
2.5 Curing 12
2.6 Emission Sources 12
3.0 Inspection Procedures 16
3.1 Preinspection Procedures 16
3.2 Control System Inspection 23
3.3 Process Inspection . 92
3.4 Plant Inspection 94
4.0 References 95
5.0 Annotated Bibliography 98
Appendices
A. Abbreviations 104
B. Glossary 105
C. Inspection Checklists 112
D. Effects of Control System Problems 123
111
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FIGURES
Number Page
1-1 General steps in a surface coating process 4
2-1 VOC sources—typical coating operation 13
3-1 Typical collection hood/ductwork fan/control device layout. . . 25
3-2 The air flow characteristics of blowing and exhausting 29
3-3 Three major hood types: (a) enclosures; (b) receiving hoods;
and (c) capturing hoods 30
3-4 Typical incinerator system 47
3-5 Carbon adsorption process 56
3-t> Fluidized-bed carbon adsorption system 59
3-7 Adsorption flow streams 60
3-8 Adsorbent regeneration and vapor recovery or disposal
alternative 61
3-9 Decanter for separating nonmiscible liquids 62
3-10 Absorption system with stripping tower 74
3-11 Cross section ot a packed tower for gas absorption 75
3-12 IJubble-cap tray tower 76
3-13 Basic surface condenser system 83
3-14 Shell and tube surface condenser 85
3-15 Contact condenser 85
IV
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TABLES
Number Page
1-1 Published EPA Studies of Industrial Surface Coating Categories
Through December 1981 5
2-1 Coating Application Methods 11
3-1 Specific Capture System/Control Device Data 18
3-2 Checklist for Hoods 34
3-3 Checklist for Ductwork 37
3-4 Checklist for Fans 41
3-5 Checklist for Incinerators 51
3-6 Checklist for Adsorbers 67
3-7 Checklist for Absorbers 79
3-8 Checklist for Condensers 87
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SECTION 1.0
INTRODUCTION
1.1 PURPOSE AND USE OF THIS GUIDE
This guide has been developed for the purpose of providing assistance to
state and local agency personnel when they are preparing for and conducting
inspections of surface coating facilities. It is intended for use by field
inspectors and entry-level engineers whose familiarity with surface coating
operations and their emission controls may be limited.
This is not a technical design manual for surface coating processes and
associated emission controls. This guide provides only basic descriptions of
surface coating unit operations and emissions. Its primary focus is on the
capture systems (hoods and ductwork) and control devices (adsorbers,
incinerators, etc.) used to collect and eliminate the emissions from
industrial surface coating processes. However, a detailed presentation of
engineering data and design theory is not provided for these capture/control
systems. Instead, detailed information regarding the purpose, operation and
maintenance of these systems is provided as guidance to an inspector who is
involved in field surveillance and monitoring of sources for continuing
compliance. Guidance is also provided on where to look for and how to
identify existing or potential operation and maintenance problems. It is
stressed that the procedures presented in this guide are for follow-up
inspections related to checking the continuing compliance of a source which
has previously proven compliance with applicable regulations.
The capture/control systems concentrated on in this guide are normally
employed on surface coating operations to reduce the quantity of volatile
organic compounds (VUC) emitted to the ambient air from those operations.
Although other pollutants are emitted from surface coating operations, VOC
receive emphasis in this document because their emission from surface coating
operations can be significant and because these compounds are one of the prime
reactants involved in the formation of photochemical oxidants (smog). At
surface coating facilities, VOC are emitted as a result of the intentional
evaporation of solvents from coatings during the application and curing
(drying or hardening) steps in the process.
In recent years, most states have promulgated regulations which limit the
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employed both approaches in efforts to comply with emission limits. The
procedures for determining that a surface coating operation complies with an
emission limit are too complex to be addressed in this document. Therefore,
emphasis is placed on the mechanical aspects of capture/control system
operation, maintenance, and equipment condition that will allow a qualitative
assessment of compliance status relative to originally permitted conditions.
1.2 ORGANIZATION OF THIS GUIDE
This guide consists of five sections and three appendices. The last part
of this section provides background information on industries that perform
surface coating as a major step in their overall production processes.
Section 2.0 presents a general description of the overall surface coating
process. Block flow diagrams illustrate the typical unit operations that are
used to form a surface coating line. The relative magnitude of VOC emissions
from these unit operations are presented.
Section 3.0, Inspection Procedures, and especially subsection 3.2,
Control System Inspection, is the primary focus of this guide. Equipment used
to capture and eliminate VOC emissions from surface coating operations are
described in detail. The operation and maintenance (O&M) of these capture/
control systems are discussed and methods of identifying existing or potential
O&M problems are presented. Relationships between capture/control system
effectiveness (reductions of emissions) and O&M activities are discussed.
Procedures are presented which inform inspectors as to why, where, how, and
what to look for so they can conduct a thorough inspection of these
capture/control systems. A description of some basic, often encountered
instruments is presented. Checklists are provided in the text for field use
to guide and aid the inspector in observing and noting the condition and
operation of the capture/control systems. Additional copies of all the
checklists are also available in Appendix C. Section 3 also provides guidance
on preparing for an inspection, surface coating process inspection, and
general plant inspection.
Section 4.0 contains the reference materials used in the development of
this guide. The material presented herein has been purposely written in a
simple and general manner that might mask the true complexity of VOC capture
and control at surface coating operations. Therefore, throughout this guide,
references are made to documents which provide technical data.
Section 5.0 contains a bibliography of references relating to the surface
coating industry, volatile organic compounds, and emission controls. The
surface coating process or control equipment related subjects covered by each
document are indicated.
There are three appendices. Appendix A is a listing of abbreviations
commonly encountered in the surface coating industry or used in reference to
emission controls. Definitions of the abbreviations and other words and terms
used in this guide are provided in Appendix B. Appendix C contains the
checklists discussed in Section 3 of this guide.
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1.3 SURFACE COATING INDUSTRIES
1.3.1 General Description
Surface coating involves the application of a wet or dry coating material
to the surface of another material. Steps prior to application include
preparation of the coating and cleaning of the material to be coated.
Subsequent to the application step, the coated material is exposed to heat,
light, or invisible radiation to dry or cure the coating. Figure 1-1 depicts
the major steps in the surface coating process.
Coatings are applied to a wide variety of materials (substrates). These
materials include metal, wood, paper, plastic, and cloth. The shapes made
from these materials, and subsequently coated, vary from flat wood panels to
automobile and truck bodies. The composition of a coating is dependent on the
substrate to which it will be applied, the shape of the object to be coated,
and the desired characteristics of the coating once dryed or cured. Likewise,
the method used to apply the coating is related to the characteristics of the
coating and the shape to be coated. The curing or drying method used also
depends on the coating characteristics and the coated object's shape.
Additional information on coatings and application and drying/curing methods
is given in Section 2.0 of this guide. The point made here is that nearly
every surface coating operation is different.
1. J. 2 Surface Coating Industries
Regardless of the large number of different surface coatings available,
some similarities exist when surface coating operations are grouped according
to the products they produce. The U.S. Environmental Protection Agency (EPA)
has used this approach to study different industrial surface coating
categories in its efforts to develop Control Techniques Guidelines (CTG) and
New Source Performance Standards (NSPS) for VOC emissions. Table 1-1 is a
list of industrial surface coating categories and the EPA published CTG and/or
Background Information Document (BID) for those categories that are the
results of the liPA1 s studies. The CTGs and BIDs are excellent references for
those who desire a more industry-specific and detailed discussion of the
surface coating processes than is available in this guide.
Note that the 11 source categories in Table 1-1 are only those for which
the EPA has completed studies. However, the variety of surface coating
operations covered under the Miscellaneous Metal Parts and Products category
gives an indication of the diversity of surface coating operations.
1.3.3 Areas of Commonality
In spite of the diversity of the surface coating industries, there are
areas and operations that are common among them. One obvious area is the
common use of solvents synthesized from petroleum products. Further, most
surface coaters will use one of four general coating application techniques;
roller, dip, flow coat, or spray. Finally, where coating operations have
applied add-on control technology to reduce VOC emissions, the control system
will be comprised of two major components; a capture system (hooding, ductwork,
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SURFACE
PREPARATION
COATING
STORAGE
COATING MIXING
& BLENDING
SOLVENT
STORAGE
COATING
APPLICATION
AREA
COATING
DRYING/CURING
AREA
FINISHED
PRODUCT
STORAGE
COATED
PRODUCT
"FLASHOFF1
AREA
FINISHED
PRODUCT
"TOUCH-UP"
AREA
Figure 1-1. General steps in a surface coating process.
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TABLE 1-1. PUBLISHED EPA STUDIES OF INDUSTRIAL SURFACE COATING CATEGORIES THROUGH DECEMBER 1981
Category
Control Technique Guideline (RACT)* title
Background Information Docunent (NSPS) title^
Can* Control of Volatile Organic Emissions from Existing
Stationary Source* - Volum II: Surface Coating of Cant,
Coils, Paper, Fabrica, Autoaobile*, and Light-Duty Truck*.
EPA-4SO/2-77-008, U.S. Environmental Protection Agency,
Office of Air Quality Planning and Standard!, May 1977.
Metal Coill See Can* above.
Paper See Can* above.
See Can* above.
Sec Can* above.
Fabric*
Autonobile* and
Light-Duty Truck*
Hatal Furniture Control of Volatile Organic Emiagion* from Existing
Stationary Source* - Volume III: Surface Coating of
Metal Furniture, EPA-450/2-77-032, U.S. Environnental
Protection Agency, Office of Air Quality Planning and
Standards, December 1977.
Magnet Hire Control of Volatile Organic Emissions frora Existing
Stationary Sources - Volume IV: Surface Coating for
Insulation of Magnet Wire. EPA-450/2-77-033, U.S.
Environmental Protection Agency, Office of Air Quality
Planning and Standard*, December 1977.
Beverage Can Surface Coating Industry - Background Information for Proposed
Standards. EPA-4SO/3-80-036a. U.S. Environmental Protection Agency, Office of
Air Quality Planning and Standards, September 1980.
Hetal Coil Surface Coating Industry - Background Information for Proposed
Standards. EPA-450/3-80-035a. U.S. Environmental Protection Agency, Office
of Air Quality Planning and Standards, October 1430.
Pressure Sensitive Tape and Label Surface Coating Industry - Background
Information for Proposed Standard*. IPA-4>0/l-«0-OOJa. U.I. «flvlreM«nt«l
Protection Agency, Office of Air Quality Planning and Standard*,
September 1980.
None
Automobile and Light-Duty Truck Surface Coating Operation* - Background
Information for Proposed Standard*. EPA-450/3-79-030*. U.S. Environmental
Protection Agency, Office of Air Quality Planning and Standard*.
September 1979.
Surface Coating of Metal Furniture - Background Information for Proposed
Standard*. EPA-450/3-80-007a. U.S. Environmental Protection Agency, Office of
Air Quality Planning and Standard*, April 1980.
None
(continued)
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TABLE 1-1 (continued)
i'o:iirol "Venn ii; ix-
(i(AXT)a title
Large Appliances Control jf Volatile Orr.ar.ic Emissions fron Existing None
Siacianary Sources - Voljne V: Surface Coating of Large
Appliances. Er.\-i50/:-77-C34, U.S. :n-.-irome7.:al
?T-3tec:ion Aje-.cy. 0:fl:e c: Air Quality Pian-.ir.J and
•-:*:a*. Pzrts and Ccnrro: :f Vola:i'.e Organic Zr.issiar.s frcn Exist:-.;
?rjJ'-r:» 3'.a:iorary 5-urccs - V?iur.» VI: Surface Coa:ir
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and fans) Co collect the VOC emissions at their point of origin in the process
and a control device that prevents release of the captured VOC to the ambient
air. The principal control devices are all based on one of four techniques;
incineration, adsorption, absorption or condensation.
It is because capture systems and control devices are so widely used to
reduce VOC emissions from surface coating operations, regardless of industrial
category, that this guide has been developed. The inspection procedures
presented here apply to any VOC capture/control system since these systems are
basically the same in all industrial categories. That is, an incinerator
employed to reduce VOC emissions from a can coating line will have common
operation and maintenance requirements with an incinerator on a metal
furniture coating line.
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SECTION 2.0
SURFACE COATING OPERATIONS
Although surface coating operations vary substantially, a typical surface
coating process consists of four major steps:
• surface preparation
• coating preparation
• coating application
• curing
The sequence of these operations was presented in Figure 1-1.
2.1 SURFACE PREPARATION
Preparation of the surface to be coated is necessary to ensure proper
bonding between the surface and the coating. The extent of surface
preparation depends on factors such as the condition of the material surface,
the method in which the coating is to be applied and the ease with which the
coating will adhere to an untreated surface. Preparation methods include
cleaning and texturing.
Surfaces are cleaned to remove dirt, grease, dust, corrosion and other
contaminants. Common cleaning techniques include degreasing and caustic
washing. The material to be coated may be simply dipped or washed or it may
undergo a more rigorous mechanical cleaning.
Texturing refers to increasing surface roughness, mostly on metal and
wood surfaces. Roughness can be increased in a number of ways including
contact with high-speed abrasives such as sand, grit and shot blasting or by
manual methods such as sanding, scraping and brushing.
After cleaning and brushing a surface is usually rinsed to ensure
complete removal of contamination.
2.2 COATING PREPARATION
Specifications for coating formulations often require the introduction of
additional ingredients prior to application. These additive ingredients
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affect certain formulation properties such as viscosity, color and evaporation
r/ile. IJloiiding ol lliest; ingredients is necess.-iry in order to ensure a
homogeneous mixture.
2.3 TYPES OF COATINGS
Different types of coatings are used in different surface coating
applications. A typical coating consists of solids (e.g., pigments, metals,
plasticizers) and a carrier (e.g., organic solvents, water). Some coatings
contain no carrier but use other methods of dispersing the solids over the
surface (e.g., electrostatic deposition).
The most common coating types are:
• solvent-borne
• water-borne
• powder
• high solids
• prepolymer
Solvent-borne coatings contain mostly volatile organic solvents. Water-
borne coatings contain mostly water with some organic solvent (typically less
than 20 percent by volume) added to enhance evaporation. >>>^ Powder
coatings use no carrier solvent. They typically consist of thermoplastic or
thermoset powder resins which are electrostatically applied to a surface and
subsequently heated to a molten state. 2
High solids formulations are solvent-borne but have a higher solids
content (typically 60 to 80 percent by volume) than normal solvent-borne
coatings. Prepolymer coatings consist of low molecular weight oligomers or
monomers dissolved in acrylic monomers.^»^ When the monomers are heated or
irradiated they link together to form polymers.^»^ A photosentisizer is
often added to catalyze the crosslinking reactions that take place in the
polymerization process.
2.4 COATING APPLICATION
A majority of coatings are applied to a surface in one of four ways:
• spray
• roller
• dip
• flow
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Many variations of these four methods exist. These variations are presented
in Table 2-1. Other coating techniques used less frequently include brush,
tumble, wipe and gas polymerization.
Spray coating involves atoraization of the coating mixture into finely
dispersed droplets. Both liquids and powders can be applied by a spray.^
lilectrostatic spraying is a technique in which the atomized coating droplets
arc electrically-charged and the article to be coated is grounded. The
charged droplets are electrostatically-attracted to the surface where they are
evenly deposited.1 Other spray coating methods include airless (hydraulic
pressure) and hot melt.^
Roller coating is used when the surface to be coated is a flat and thin
substrate (e.g., adhesive tape, newspapers, wood panels). Rollers are used
for guiding the substrate, applying the coating, and maintaining tension.^»°
Many individual roller coating techniques exist for uses in different
applications, as shown on Table 2-1.
Dip coating is commonly used to coat irregularly-shaped articles such as
appliances, metal furniture and automobile parts. Articles and parts to be
coated are typically attached to an overhead coveyor and lowered into a dip
tank. The parts are then raised out of the tank and the excess coating is
allowed to drip off. Surfaces can also be electrocoated by applying a current
to the dip bath.*» ^
Flow coating essentially involves showering the article to be coated.
The article passes under the opening of a trough or tank filled with liquid
coating material. The liquid flows out and over the surface. Excess liquid
is allowed to drip off over a drain board.
A surface may require the application of several different layers of
coating for the purposes of protection and appearance. Five sequential layers
which may be applied in a coating process are:
• primer
• sealer
• print
• topcoat
• touchup
The prime coat is applied directly to the prepared substrate. Sealers are the
next coat(s) and are used to develop thickness. Any printing or lithography
is applied on top of the sealer. The topcoat or finish coat is the final
layer and is almost always for appearance. If a finish is marred in any way
it will receive final touchup coating where required.' Not all coating
operations perform these steps; some apply only a primer and topcoat while
others apply only one coat (e.g., printing).
10
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TABLE 2-1. COATING APPLICATION METHODS
Spray Roller
• atomized air • direct roll •
• atomized airles • reverse roll •
• electrostatic • blade •
• powder • knife •
• air knife
• gravure
• lithographic
• flexographic
• die fountain
• fibrous belt
• metering rod
• puddle
• kiss-roll
• meniscus
• size press
• nip roll
• calendar
• cast
Dip Flow Miscellaneous
electrodeposition • flow • brush
dip and squeeze • curtain • tumble
electrostatic fluidized bed • wipe
hot melt • gas polymerization
Source: Reference 7
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The number of times each layer is applied is a function of the wear and
tear the object will experience during its use.° For example, a coating
that will be exposed to a marine environment will consist of more layers than
» co/i ting applied to wood furniture. Many coating facilities also purchase
precoated material which reduces the number of layers which must subsequently
be applied. 9
2.5 CURING
Curing of a coating is performed to either:
• dry the coating by evaporation of the solvent
• remelt the coating and cover scratches, streaks and bubbles, or
• polymerize a prepolyraer coating
Different curing methods are used as a result of the desire to dry the
coating as quickly as possible without causing deterioration. The most common
forms of curing are:
Oven baking - the article or substrate passes through an oven where a
heat source evaporates the solvent. Forced hot air is the usual heat
source. Other heat sources are radiative types; infrared, ultraviolet
and electron beams. Ovens can be either single or multipass and
frequently have zones of varying temperature to ensure uniform drying.
Flashoff - an area of elevated temperature which precedes an oven in many
facilities. A flashoff area allows solvent to slowly vaporize from the
coating film. This helps prevent "popping" of the coating during baking.
Air drying - used for articles too large to fit in an oven (e.g.,
industrial, construction and transportation equipment) or for articles
which contain heat sensitive materials. Air drying is typically
performed in an open room.
Usually the coated material will be passed through a curing step after
each subsequent application of coating. The curing method may be different
for each of these curing steps in the overall surface coating process.
Most curing is performed on a continuous basis (e.g., on a conveyor belt)
although some articles, such as wood furniture, must dry for long periods of
t ime.
2.6 EMISSION SOURCES
Most of the pollutants in a coating application operation are emitted
from application and curing of the coating. Table 2-2 lists typical sources
in each category. Other emission sources include storage and handling,
coating preparation, and equipment cleaning. Figure 2-1 displays the sources
of VOCs in a typical coating operation.
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voc
FROM
SURFACE
PREPARATION
t
APPLICATION
VOC
T
FLASHOFF
AREA
VOC
•*»
/
i
CURING
OVEN
FINISHED
' PRODUCT
FLOW
Figure 2-1. VOC sources—typical coating operation.
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TAHLK 2-2. EMISSION SOURCES IN COAT [NU OPERATIONS
Application Curing
• primary • flashoff •
• sealing • oven •
• printing • air drying •
• topcoat •
• touchup
Other
equipment cleaning
surface texturing
coating blending
coating storage
The relative magnitudes of emissions will vary according to the type of
coating process. Some facilities experience greater emissions from the
application and flashoff areas while others have greater emissions from
curing. Table 2-3 provides a relative breakdown of emission source magnitude
for several coating operations.
TAiiLE 2-3. RELATIVE EMISSION SOURCE MAGNITUDE 1» 9» 10» U
Percent emissions by source
Coating operations Application and flashoff Curing
Metal Cans
Large Appliances
Metal Furniture
Miscellaneous Metal
Parts and Products
40
64
50
69
60
36
50
31
Coating facilities must dilute VOC emissions with excess air for two
reasons:
1. To reduce the possibilities of explosions or fire.
2. To maintain VOC concentrations below the level determined to cause
adverse health effects in humans.
14
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Insurance companies typically require that coating facilities maintain VDC
concentrations in the air below 25 percent of the solvents' lower explosive
limit (LED. Occupational safety standards often require an even lower
concentration, particularly when a solvent is thought to pose significant
adverse health effects. Some newer coating lines are allowed to
operate with higher VUC concentrations (up to 50 percent LEL for oven exhaust
only). This is only permitted if the facility performs continuous
concentration monitoring and installs alarms and automatic shutdown devices.'
Even coatings which contain little or no organic solvent can produce some
form of emissions such as:
• Electrodeposition - although these are mostly waterborne coatings,
the formulations often contain amines which cause odors and visible
emissions when incinerated.
• Prepolymers - these emit volative monomers during curing.
• Powder coatings - these emit volatile monomers during the
crosslinking reaction.
Other pollutants which can be emitted from coating facilities include
particulates from sanding operations and combustion products (NOX, 802)
from direct-fired curing ovens.
The diversity of surface preparation, coatings, coating application
techniques and curing methods makes it impossible to present all combinations
that will be encountered during an inspection. A brief description of all the
possibilities in these areas has been presented to make the inspector aware of
the range of choices available to the plant personnel. The inspector should
have a basic understanding of why the various operations are being undertaken,
so that questions in these areas can be geared to those items which will
affect VOC release, such as "what is the specific VOC content of that
coating?" and "is the coating applied by spray (which tends to release more
VUC per item coated) or dip?" A knowledge of the types of coating and curing
techniques used in a facility is especially helpful in ascertaining how the
VOC are captured and controlled, once they are deposited on a surface.
Certain application techniques are usually associated with specific hood
designs, and being able to recognize the method of coating application will
guide you to the collection hood being used to capture the VOC. The types of
capture systems used in surface coating facilities will be discussed in the
next section.
15
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SECTION 3.0
INSPECTION PROCEDURES
3.1 PREINSPECTION PROCEDURES
A certain amount of preparation prior to an inspection is always
advisable. The preinspection procedures suggested here are intended as
general guidelines on how to prepare for and begin the inspection of a surface
coating operation. However, the procedures are only suggestions; you must
become familiar with and follow the procedures established by your agency at
all t imes.
It is important to remember that you represent your entire agency at all
times during the inspection. The legal authority that you represent during
the inspection will depend on your agency's enabling legislation. Make
certain that you are aware of the limits of your authority. Both your agency,
and you personally may be liable for your statements or actions while in the
presence of a source's representatives or on a source's property. Do be
professional, courteous and cooperative. Do not offer opinions or make
statements in areas where you have limited experience or knowledge.
As stated in the Introduction, these procedures are for continuing
compliance inspections. These are inspections of sources which have
previously proved initial compliance with regulatory emission limits by
installing air pollution control systems and/or modifying processes. A
properly conducted continuing compliance inspection will, at a minimum, allow
a qualitative comparison of present equipment operation and condition to the
initially permitted conditions.
3.1.1 File Review
The first step in preparing for an inspection is a review of all
information available in your agency's files on the surface coating operation
that you will be inspecting. Efforts invested in reviewing the available
information will reduce your onsite field time because you will know exactly
what information you must collect.
First, conduct a general review of the documents on file. Note records
of citizen complaints, previous inspection reports, and equipment
malfunctions. Look for plot plans which show the layout of the facility, the
location of equipment, and identification of emission points. You should be
able to locate documents that provide specific design and operation data for
processes and control equipment.
16
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Next review the data specifically to determine the process or control
equipment, parameters that affect emissions from each emission point. For each
emission point, the source should have either done something (process
modification, control equipment installation) or submitted something (stack
test, material balance) that would establish initial compliance with emission
limits. The documentation that the source submitted to support its claim of
compliance should contain the detailed information you need to familiarize
yourself with the process and control equipment. However, there will be much
more information than you need for the purposes of a continuing compliance
inspection. You should concentrate on those specific values of process or
control equipment operation parameters that can influence emissions. Section
3.2 of this guide identifies key data that you should review.
You may wish to summarize some of the data or previous inspection
information so that you will have it available during your inspection. You
will have a clearer idea of what that information might be once you have read
Section 3.2 and reviewed the inspection forms/checklists there and in Appendix
C. Regardless of whether you bring notes or other information with you on
your inspection, you should be aware of the following information once you
have completed the file review.
1. The emission points and the relative magnitude of their emissions.
2. The specific steps the source has taken at each emission point to
comply with emission limits.
3. The key parameters that affect emissions from each emission point at
the source. "\
4. The processes or process areas at the source.
5. The results, recommendations, or conclusions of previous inspections.
6. The history of citizen complaints against the source.
7. The history of process or control equipment malfunctions that have
caused increased emissions.
For each capture system and control device installed on a surface coating
operation, the specific information with which you should familiarize
yourself, in detail, is presented in Table 3-1. If any of these items of
information are not available from the file you should make a note to obtain
it during your inspection.
3.1.2 Regulation Review
As you reviewed the source file you may have noticed reference to
specific regulations that apply to the emission points at the source. Review,
in particular, those regulations that apply to the emission of VOC from
surface coating operations. Discuss the regulations with experienced
personnel at your agency to make certain that you understand what they say,
how they are applicable, and how they are interpreted.
17
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TABLE 3-1. SPECIFIC CAPTURE SYSTEM/CONTROL DEVICE DATA
1. GENERAL
A. Number of coating lines at plant
II. Number of control systems at plant
C. Major noncoating line related emission sources at plant
II. SURFACE COATING PROCESS
A. Material being coated
B. Production rate
C. Coating applied
D. Coating application method
E. Coating application rate
F. Drying/curing method
G. Drying/curing temperature
III. CAPfURE SYSTEM
A. Total number of hoods in each system.
B. Type of hoods
C. Distance of each hood from source
D. Design capture/face velocity at each hood
E. Location of filters
F. Location of dampers
G. Type and location of fan(s) in system
H. Horsepower, voltage, amperage of fan motor
I. Type of fan drive (direct, belt)
J. RPM of fan
K. Design flow rate of system
IV. CONTROL DEVICE
A. Type of control device
B. Inlet pollutant concentration
C. Outlet pollutant concentration
D. Air flow through device
E. Design efficiency
F. Depending on the type of control device, review Tables 3-5
through 3-8
G. Disposal procedure for pollutant removed from control device
18
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Ln addition to regulations that establish emission limits, your agency
may have regulations that require certain operation, maintenance, record
keeping, or reporting activities. You should also be aware of these and how
they apply to the activities at the surface coating operation you will be
inspecting.
Finally, your agency may have negotiated certain legally-binding
agreements with the subject source. These agreements are likely to be in
regard to issues unique to the activities at the source. They may allow the
source some leniency from the strict interpretation of a regulation or they
may have established requirements more stringent than a regulation. These
agreements are sometimes called variances, consent decrees, or compliance
schedules. If such an agreement exists with the source you will be
inspecting, be certain that you understand it fully before your inspection.
3.1.3 Safety Considerations
The machinery used in a surface coating line has many moving parts. The
movement is often high-speed and noisy. The odor of solvents used as diluents
and cleaners is often noticeable. The first rule for your safety at these
facilities is do not touch, lean on, or stand too close to any of the process
equipment.
The availability of safety equipment for inspector use varies between
agencies. At a minimum, a hard hat, safety glasses, and steel-toed safety
shoes should be part of your equipment compliment. (For your own well-being,
you should consider purchasing and using these items even if your employer
does not supply them.) One or more of these three items are often required
before a company will allow you to enter their process areas. Some companies
will supply you with safety glasses and a hard hat for use during your visit.
However, they are under no obligation to do so and can rightfully refuse or
delay your entry if they require these safety items and you do not have them.
The specific safety rules will vary from plant to plant. You should
discuss safety equipment and procedures when you call to announce your
inspection (see Section 3.1.4). If your inspection is to be unannounced, you
should discuss safety during the preinspection meeting at the plant. In
addition to the risk of personal injury, your failure to comply with a
company's safety equipment and procedure requirements is one of the quickest
ways to destroy a cooperative, working relationship between a source and your
agency.
The following safety measures should be kept in mind while at surface
coating facilities and are also generally applicable to all inspections.
• Do not wear loose clothing. Long-sleeved shirts and long pants made
of heavy material are appropriate. Pay special attention to
drawstrings on jackets.
• Do not carry loose items in pockets - they may fall out when you
bend, twist, or stretch.
19
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• Do not lean on things, including guardrails, they may not be as
secure as they appear.
• Do not wander around alone. You should insist on being accompanied
by a company employee familiar with plant operating areas.
• Do not touch anything or attempt to operate switches, valves,
levers, etc. without first asking for and receiving permission from
your facility escort. If you see something obviously improper,
bring it to a company employee's attention but do not attempt to
take corrective action yourself.
• Do not ignore warning signs, look for them and do not enter
roped-off areas.
• Do be constantly aware of your footing, your balance, and what is
above and around you. Look and listen continuously.
• Do keep away from the surface coating equipment. Many times it is
automatically controlled and can start without warning. Some parts
operate at such high speeds that they do not appear to be moving.
• Do be courteous to company employees. If you stop to observe
something make sure you are out-of-the-way and in a nonhazardous
spot.
• Do be aware that coating drying/curing operations may employ intense
heat, light or invisible radiation. Approach the equipment
carefully and employ protective equipment.
• Do wear ear protection in high noise areas. Remember that other
personnel in the area may also be wearing ear protection and will
not hear you approaching. Attempt to make visual contact on your
approach to avoid startling someone.
3.1.4 Inspection Announcement
It" you desire or are required to announce your inspection in advance, you
should contact the company a few days or a week before the date you plan to
conduct your inspection. The name of the appropriate plant contact should be
available from the file. Make certain that the person with whom you are
making the appointment can arrange for access to the equipment you must
inspect and has the authority to release any data and samples you will need.
You sliould be somewhat flexible on the exact date of the inspection. If the
appropriate plant contact cannot be available or if the equipment you want to
inspect will not be operating on the day you originally intended to inspect
the plant, you should give serious consideration to rescheduling the
inspection to the earliest alternative date when both the plant contact and
operating equipment will be available.
The following are topics you should cover during your inspection
announcement communication with the plant contact.
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• Establish the date and time of the inspection and the name of the
company representative to be involved.
• Identify the agency personnel who will be conducting the inspection.
• Provide a brief statement on the purpose of the inspection, the
equipment to be inspected, and anticipated data and sample needs.
• Solicit information on required safety equipment and procedures.
• Determine plant entry procedures. Get an explanation of any
documents you may have to sign to gain entry.
• Provide an estimate of how long you think your inspection will take
to complete.
• Confirm directions to the location of the plant or the place where
you will meet the company contacts.
• Solicit information on the company's attitude toward photographs and
the handling of confidential information.
• Provide instruction on who to contact at your agency should the
company be unavoidably forced to request rescheduling of the
inspection.
3.1.5 Pre-entry Observations
Your inspection can (and should) begin before you enter the plant if your
schedule allows sufficient time. The observations outlined here can also be
conducted after the in-plant inspection.
Circumnavigate the perimeter of the plant being careful not to trespass
on either the company's or other people's property. Look for visible
emissions from stacks in the plant and fugitive emissions and odors leaving
the plant property. You can legally read stack opacities without obtaining
permission from the company as long as you are not on the company's property
and provided you can position yourself properly and you are currently
certified to read visible emissions (VE). Take VE readings if you think you
see a potential violation of your agency's regulations. Note the noise levels
around the plant boundary and the proximity of homes, schools, and businesses
to the plant property line.
3.1.6 Plant Entry
You should make every effort to arrive at the gate or front office of the
plant 5 or 10 minutes before your scheduled time. Be sure to call the person
you will be meeting with if you are going to be lace.
When you arrive at the gate or front office of the plant, introduce
yourself, present identification, and indicate that you have an appointment
21
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with the prearranged plant contact. Follow your agency's instructions
regarding the signing of any forms that may limit the company's liability for
your wafety or restrict the scope of your inspection.
If you must pass through the plant gate, you may well be dealing with the
plant security guards. Be prepared to respond to their procedures (you may
have to leave matches, lighters, and pipes with them). If their instructions
disagree with verbal arrangements you have made with the company
representative you will be contacting, request that they discuss the matter
with that representative.
If you are conducting an unannounced inspection, access to the plant may
require more time. However, if you are denied entry to all or part of the
facility, regardless of whether the inspection is announced or not, you should
note the reasons for refusal, the name and title of the company official
responsible for the refusal, and the date and precise time of refusal. Notify
your supervisor of the refusal by telephone immediately. Never attempt to
summarize for anyone at the plant the potential legal consequence of the
company's refusal to allow you entry. Let your agency's legal staff handle
the matter.
3.1.7 Preinspect ion Meeting
It is recommended that some time be spent in a brief meeting with plant
personnel before the actual inspection is begun. The following topics are
suggested for discussion during this meeting.
• State the purpose of the inspection, the equipment to be inspected,
and the data and samples desired.
• Discuss the confidentiality requirements and procedures of the
company as they will apply to your data collection or inspection
needs.
• Solicit information regarding key personnel or ownership changes
since the last inspection.
• Review process and control equipment plot plans and flow sheets to
confirm your understanding of current operational equipment and to
identify any changes or modifications in plant operations since the
last inspection.
• Discuss the safety procedures, required safety equipment and hazard
potential of areas you will be entering.
In addition to these topics, you should be prepared to discuss areas of
concern to the plant management, such as:
• Your agency's authority to conduct the inspection.
• The organizational structure of your agency and your place and
function in that structure.
22
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• The specific applicability of regulatory requirements to the source.
• The purpose or uses for information collected during the inspection.
If you are at all in doubt about the response to a question by plant
personnel, simply state your lack of knowledge regarding the subject. Make
sure you thoroughly understand their inquiry and offer to have a person from
your agency, who is knowledgeable in that area, contact them. If you make
such an offer, write it down in your inspection notes and make sure that the
company is contacted with the information.
3.2 CONTROL SYSTEM INSPECTION
Inspection of a plant's VOC capture and control system should start with
the point of emission and proceed toward the air pollution control device. As
most surface coating facilities will have multiple emission points, you should
personally inspect as many as is reasonably possible. The diversity of
surfaces that are coated, VOC that are used in conjunction with coatings,
methods of coating application, capture hoods and VOC control devices make it
impossible to describe a "typical" facility that you will encounter in the
field. You must, therefore, assess each individual situation and diagnose the
specific combination of VOC application, capture and control devices that are
installed so as to select which checklist and/or questions are applicable. In
addition, there will be many items that can only be checked when the equipment
is not running. No one should reasonably expect a plant to spontaneously shut
down production solely for the purpose of a visual inspection, so observe what
you can given the situation. If you cannot see all parts of a device
directly, ask the Plant Engineer or other company official who is accompanying
you about the item and how it appeared when it was last checked by the plant.
While one aspect of the inspection is meant to update your agency on the
operating and maintenance (O&M) practices of the company, another aspect is
intended to let the company know that you have a direct interest in how and
when they maintain their equipment. In this regard, try to avoid asking
company personnel "Yes" and "No" questions. For example, if you ask them "Do
you lubricate this fan regularly?", they are inclined to answer "Yes," whether
they do or not. However, if you ask "How often do you lubricate the fan?",
they are forced to state their maintenance schedule or admit that they do not
have one. Just asking the question may direct their attention to the idea of
regular maintenance and, for the sake of consistency during future
inspections, make them adopt the frequency they gave you. Remember, the
overall purpose of this inspection is not necessarily to catch the plant
making inconsistent or inaccurate statements, rather it is to direct their
attention to the importance of regular operation and maintenance equipment
inspections.
To the greatest extent possible, write down all information and
observations you have on the capture and control equipment. Often, the only
way to show that the equipment is no longer controlling VOC effectively is by
the gradual change in various readings and measurements. Data taken today
needs to be compared with last year's data to know if a part is wearing down
23
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and may no longer be effective. If you can during the inspection, obtain a
copy of all log sheets that the company uses to record various control device
parameters such as temperatures, pressures and flow rates. When something is
unclear or appears to be wrong, say a noisy pump, then ask about it. Find out
about its history, how and when it was serviced and why it is making the
noise. A good inspection requires that no question is left unsaid if it
serves to clarify what the plant is doing about operation and maintenance.
The emission control system at a surface coating operation will consist
of two portions; the emission capture system and the emission control device.
In this section, the capture system is discussed first, followed by a
discussion of control devices. If either one of these two portions of the
control system is operating less effectively than originally designed,
pollutant emissions to the ambient air will increase.
The relationship between effective VOC emission capture and effective VOC
emission control can not be over stressed. The purpose of the capture system
is to collect the VOC emissions at their point of release in the surface
coating process and deliver the VOC emissions to a control device which
removes them from the air stream. The efficiency of the overall control
system is directly related to the efficiency of both the capture system and
the control device. For example, if the capture system collects 90 percent of
the VOC released by the coating process and delivers them to a control device
that removes or destroys 90 percent of them, then the overall control system
VOC removal efficiency is 81 percent (90% x 90% = 81%). If either the capture
system or the control device becomes less effective and its efficiency drops,
for example, to 80 percent, then the overall control system efficiency drops
to 72 percent. When you are quoted an efficiency by a company representative,
be certain that you find out what the efficiency applies to, either the
overall system or one of the two portions.
3.2.1 Capture Systems
3.2.1.1 Introduction—
The effective control of emissions generated by surface coating
operations requires that two sequential events occur: the emissions are
captured at the point where they are generated and conveyed to an air
pollution control device; and the control device reduces the total amount of
emissions so that they meet applicable emission standards. Unless both of
these systems work successfully, uncontrolled or inadequately controlled
emissions will be released to the ambient air. This section will address the
various aspects of the capture system and the following section will cover
control devices.
The capture system consists of three main parts: hoods that trap the
emissions, ductwork that transfers the emission to the control device, and a
fan that supplies the energy necessary to move the emissions through both the
capture and control systems. These elements are graphically displayed in
Figure 3-1. While the fan may be located after the control device, it will be
discussed here, since it affects how well the capture system works. To
24
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illll
ENCLOSURE
RECEIVING HOOD
CAPTURE HOOD
HOODS
FAN
DUCTS
DUCTWORK FAN
INCINERATOR
T
ADSORBER
ABSORBER
CONDENSER
CONTROL DEVICE
AMBIENT
AIR
DISCHARGE
Figure 3-1. Typical collection hood/ductwork fan/control device layout.
-------
understand what items must be checked in the inspection of a capture system it
is useful to know how the system works and why the various pieces of equipment
are used in the first place. The following discussion reviews the basic
principles of ventilation systems without getting into specific design
calculations. Inspections of both capture and control systems will be
conducted with the assumption that each system was properly designed for its
specific application. These inspection procedures will be aimed at
determining (1) if the system no longer works as it was designed, owing to
poor equipment maintenance or improper operation, or (2) if the system has
been modified, through the addition of additional hoods, ductwork, etc. such
that the original design is now insufficient. Regardless of how well the
system was originally designed, the main purpose of these inspections is to
determine if the capture and control system is properly operating now.
The flow of air between any two points is due to the occurrence of a
pressure difference between the two points. This is true for large air masses
such as weather systems as well as for small in-plant air movement. This
pressure difference results in a force on the air causing air flow from the
high pressure zone to the low pressure zone. In ventilation and air pollution
control systems, the pressure difference is created by generating a low
pressure in the system by means of a fan. The fan has to develop enough
suction (low pressure) to pull the desired amount of air into the hoods and
through the ducts and control device to the point of discharge. The suction,
or low pressure, generated by the fan is called negative pressure because it
is lower than ambient or atmospheric pressure. The measurement units for
pressure are usually pounds per square inch (psi) or inches of water gauge
(in. wg.).
Air traveling within a ductwork will exert two forces. One is called
static pressure and is due to the air being confined within the ductwork.
Static pressure is the same pressure exerted on a balloon when you blow it
up. It is there whether there is motion or not, and it can be positive
(acting to burst the balloon, piping or ductwork) or negative, (acting to
collapse the ductwork).
The second component is called velocity pressure and is the force which
results from the air moving through the ducts. Velocity pressure is the force
you feel if you hold your hand outside the window of a moving car. It is
proportional to the square of the air velocity.12 This relationship between
velocity pressure and velocity is useful in other areas of air pollution
control, such as stack testing, because it enables us to calculate the
velocity of an airstream by measuring its velocity pressure. Air pressure
measuring gauges, used for this purpose, are called manometers. Manometers
can be simple "U" tubes, they can be inclined, as the ones in stack testing
are to give greater accuracy, or they can be in the form of easy to read
gauges, such as a magnehelic gauge. Manometers can also be used to measure
total system pressure, which is the combination of static and velocity
pressures. This measurement is important in determining the pressure at any
point(s) in the system and the difference in pressure between any two points.
This aspect of pressure readings will be discussed later in this section.
26
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Air flowing through ducts encounters resistance to flow due to friction
and turbulence. Friction is caused by the air rubbing against the walls of
tlit! ducts. If the duct walls are relatively smooth, the friction will be
low. If, however, the duct walls are irregular or uneven due to corrosion,
rust or dents, the friction will be much greater. Friction also increases with
higher air velocities, longer runs of ductwork, and smaller duct diameters.*2
If any one of these items is changed in this way, the system will have more
friction than was originally designed.
Turbulence takes place whenever the duct changes direction or varies in
crosssectional area. Smooth ductwork junctions cause little turbulence, while
sudden changes in direction or abrupt contractions or enlargements cause a
great deal of turbulence.
e
The combined affects of friction and turbulence cause a resistance to
flow in the ductwork that is called a pressure drop. This pressure drop, like
static and velocity pressure, is measured by a manometer in terms of inches of
water. The resistance resulting from friction and turbulence must be overcome
by adding more energy to the system and this is accomplished by the fan.
Pressure losses also result from the turbulence that is caused as the
airflow enters the hood. Gradually tapered or bell mouth shaped hoods cause
little "hood entry" losses, while right-angles flanged hoods and completely
unflanged hoods result in significant pressure losses." These losses, like
friction and turbulence, must be overcome by increasing the energy supplied by
the fan.
A ventilation system is designed with all of these factors in mind. The
shape of the hood mouth, the number and interconnection of the various
branches of the total system, the dimensions of the ductwork and the volume of
air required for a specific application all affect the selection of a fan.
Once the system is designed and installed, any changes that occur, such as
adding additional branch connections, changing to a smaller duct diameter or
an accident which noticeably dents the ductwork could add to the total system
resistance. If this happens, the company must alter the original design by
operating the fan at a higher speed or by installing a new, larger fan. If
the fan is not changed, then the increase in system resistance due to these
changes will cause the fan to pull less air, and this will decrease the
effectiveness of the system to capture pollutants. This is a chief concern in
the inspection, since the system resistance can increase slowly over time, and
the plant personnel might not even be aware of it, or the slow decrease in VOC
capture efficiency, that goes along with it.
One additional item that must be mentioned at this point is capture
velocity. Capture velocity is the air velocity in front of a hood that is
necessary to capture the contaminated air.^^ The minimum capture velocity that
is required for any situation depends on several factors including the type of
pollutants to be captured (solid or gas), the velocity with which the
pollutant is emitted into the air, the shape of the collection hood and the
presence of room air currents. This velocity is established by the volume of
air being pulled through the hood by the fan and the size (area) of the hood
27
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opening (velocity=volurae/area). It is designed into the system by controlling
the volume of air that is allowed to flow in the ductwork and by the size and
shape of the hood at the emission release point. The capture velocity must be
great enough to remove the contaminated air around the source and to overcome
any cross ventilation in the room. Contaminants such as VOC, that are usually
released with no velocity require a smaller capture velocity than do
contaminants such as solids from grinding and sanding operations, which may
have a high initial velocity, and therefore require a high capture velocity in
order to completely trap them in the capture system. Also, contaminants of low
toxicity (such as VOC) released with low velocities in a room with low air
currents and captured in a large hood will require a capture velocity much
lower than those released with high initial velocities into a drafty room and
captured by a small hood.13
The problem confronting the inspector is to observe the system in
operation and to determine if it is working as designed during the
inspection. Are the pollutants generated in the surface coating operation
captured by the hood? As you shall see, some hood designs are more "tolerant"
to changes that affect original design. They will continue to capture
pollutants even when air flow rates decrease. Other designs will lose their
effectiveness fairly rapidly if the capture system has been altered or has
been allowed to deteriorate.
3.2.1.2 Hoods—
The hood is the most important part of the capture system. If
contaminants are not initially captured as they are emitted from the surface
coating applicator, flash-off area, curing oven, or other emission point, the
entire capture and control system will be ineffective in limiting emissions.
Before we discuss hood design, however, there is a common fallacy about air
flow in and around hoods that must be dispelled. This has to do with the air
flow characteristics of blowing and exhausting (see Figure 3-2). Air blown by
a fan through a small duct opening retains its directional effect (forward
velocity) for a considerable distance beyond the duct opening. You may have
noticed this effect when you feel the force of a window fan across an entire
room. When blowing, approximately 10 percent of the initial velocity of a fan
still exists at distances equal to 30 duct diameters from the duct opening.12
However, the same effect is not true when a fan is used in reverse, to exhaust
air from a room or from an emission source. In this case, the air loses its
initial velocity very quickly as you move away from the duct opening. You
have to go very close to the back (suction side) of a room fan before you can
feel the effect of the fan's suction. Expressed another way, when exhausting,
approximately 10 percent of the initial capture velocity created by a fan
still exists at a distance equal to only 1 duct diameter from the exhaust
opening. The effect of a fan is 30 times greater when it is blowing compared
to when it is exhausting! This effect is very important in designing exhaust
hoods since it is the exhausting mode of the fan that is used. This effect
says that you have to place the hood very close to the emission source if you
want to maintain a set capture velocity across the entire face of the source.
A hood is generally defined as any point where air is drawn into the
ventilation system to capture or control contaminants. There are three major
types of hoods, each working on a different principle (see Figure 3-3).
28
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30 d
400 FPM
N
I
4000 FPM AIR
VELOCITY AT
FACE OF BOTH
APPROXIMATELY 10% OF FACE VELOCITY
AT 30 DIA. AWAY FROM PRESSURE
JET OPENING.
EXHAUSTING
APPROXIMATELY 10% OF FACE VELOCITY
AT ONE DIA. AWAY FROM EXHAUST
OPENING.
400 FPM
Figure 3-2. The air flow characteristics of blowing and exhausting.
29
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Fan
(a) Enclosures - contain
contaminants released
Inside the hood
/-Contaminants
rising from
hot process
(b) Receiving hoods - catch
contaminants that rise or
are thrown inlo them
Capturing hoods - reach
out to draw in contami-
nants
Figure 3-3. Three major hood types: (a) enclosures;
(b) receiving hoods; and (c) capturing
hoods.l^
30
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1. Enclosures are hoods that surround the contaminant sources as much
as possible. Contaminants are kept inside the enclosure by air
flowing in through openings in the enclosure. The more complete the
enclosure, the less airflow is needed for control. Employees
generally do not work inside enclosures while contaminants are being
generated, although they may reach into the enclosure as long as
they do not breathe the contaminated air. Enclosures are most
commonly found in laboratory applications, where intermittent use of
more hazardous chemicals are involved. Certain totally-enclosed
surface coating operations, such as curing ovens utilize the design
principles of enclosures. Because they totally enclose the emission
source, enclosures are less prone to system upsets.13
2. Receiving hoods are designed and positioned to catch contaminants as
they are released by the process. These contaminants may be
particulates from a grinding operation or VOC from surface coating.
In each case the hood is located in such a fashion to take advantage
of the natural flow of contaminants. These hoods allow workers to
operate in and around the process, however, their effectiveness is
susceptable to cross drafts in the workroom.^^
3. Capturing hoods make full use of the capture velocity to draw in
contaminants from the process. This hood is widely used since it
can be placed alongside the contaminant source rather than
surrounding it as with an enclosure. The primary disadvantage is
that large air volumes may be needed to generate an adequate capture
velocity at the contaminant source. A second disadvantage is that
the "reach" of most capturing hoods is limited to about 2 feet from
the hood opening. This reach will decrease if the system air flow
decreases. In this case pollutants released at a point furthest
from the hood will not be captured and will escape into the room.
These escaping pollutants can be observed and are indicative of a
poorly functioning capture system.^-*
Any inspection of a surface coating facility will probably reveal one or
more of the three major types of hoods. The problem confronting the inspector
is to ascertain if the hood that is installed is working properly by capturing
all emitted contaminants. This might be especially difficult since VOC are
not as easily visible as particulates. Nonetheless, by using several of your
senses, including sight, smell and touch, you can determine if any pollutants
are escaping the hoods.
VOC emissions can often be distinguished by their vapor trails. They
have the appearance of "wavy lines" when compared to a background. This
phenomena can also be observed with spilled gasoline evaporating from a
service station in the summer. These emissions would be noticeable at the
entrance to an enclosure-type hood, on the perimeter of a receiving hood or on
the side of the emission source that is furthest from a capture hood.
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Escaping emissions might also cause a distinct odor in the room where the
hood is located. The existence of this odor depends on the type of VOC and
its concentration. Yet, if it is present it can signal a capture system
problem.
Touch can ulso help diagnose a malfunction. While capture velocities for
VOC emissions are usually very low, placing your hand near the capture hood
can sometimes help detect if there is a noticeable air flow toward the hood,
indicating that sufficient draft exists in the system. Conversely, if you
feel an air velocity going up and around the hood, it is a good indication
that there are escaping emissions.
There are several instruments available that can help you determine if
there is an air flow into a hood, or if the air (and VOC) is bypassing the
hood and going into the plant. One instrument is the velometer, also called a
swinging vane anemometer.^ This device is small, compact and portable and can
be held in one hand. A small tube is inserted into the instrument, and the
other end of the tube is held in and around the hood. With the velometer you
can measure the exact velocity of the air flowing into the hood and capture
system. If your agency has such a device, you should bring it with you to the
inspection. Get familiar with how the instrument works when you are in your
office. This will minimize time spent in taking measurements at the plant.
If you do use the velometer, take several readings in and around the hood(s)
you suspect as not working properly. Carefully note the location and velocity
of each reading you take on your inspection checklists. Once back in the
office you can check this data against the original design. Also, you can
keep this data as a comparison to data obtained during the next inspection of
this plant.
Another instrument that might prove valuable in inspecting capture hood
efficiencies is the smoke tube.^ This device emits a smoke trail and you can
place it near a hood to see if the smoke flows into or around the hood. Smoke
tubes can only give a rough estimate of airflow, they will not tell you exact
air velocity. Nonetheless, this is all you need at times, and it can prove
very useful if you cannot determine if VOC are flowing into a hood or not.
Even if you do not directly see escaping VOC emissions, you should look
for secondary signs that may indicate a potential problem. Use your common
sense as you look around each hood. Are there any signs of VOCs that have
condensed in or around the hood? Does the hood surround the emission source?
Perhaps the original machine which the hood controlled has been replaced by a
larger one, and the hood was not enlarged. Is the operation running at
maximum capacity'! Maybe the hoods work well at low operating and emission
rates, but cannot do the job when they are at 100 percent operation. Does the
hood have any type of filter? If it does, how often is this filter changed
and when was it last changed? A clogged filter can increase capture system
resistance, cause lower air flows, and may make the hood ineffective. How
does the hood look? Is it physically intact, or are there noticeable holes?
In general, you must look for any obvious or secondary indication that the
system is not working and that VOC are not being completely captured by the
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collection hood. Table 3-2 is a checklist for hoods which should be completed
for every hood you inspect. It covers the main items that must be checked
during each hood inspection. A copy of this checklist is also included in
Appendix C. A table which summarizes some problems that may arise with hoods,
and the effects that these problems would have on operations or emissions can
be found in Appendix D (see Table D-l).
3.2.1.3 Ductwork--
Ducts and ductwork for containing and transporting the contaminated air
stream to an air pollution control device are relatively simple. They contain
no moving parts that require regular servicing and maintenance and once
installed this part of the capture system should last indefinately. The
principal considerations that go into designing a ductwork system are: keep
the system resistance to airflow low by using as large a ductwork as is
economically possible and by minimizing the number of bends, elbows and abrupt
changes in duct diameter; balance the airflow resistance in the various
branches of the system so that the capture velocity at each hood meets design
criteria and insure that the air velocity within the ductwork is sufficient to
transport the pollutant being controlled. *••*
Overall ductwork resistance must be minimized to reduce power costs. The
greater the resistance to flow, the larger the fan must be to overcome
friction in the system, and the greater the total power costs. Similarly,
bends and elbows provide more resistance than do straight sections of
ductwork, so the ideal design uses a minimum number of these pieces. Small
diameter ductwork is cheaper to buy initially, but produces more resistance,
so a balance must be struck between low initial cost (small ductwork) and
small operating costs (large ductwork).
Balancing a total ductwork system to provide for equal or appropriate air
flows in all hoods can be very complex. Many system designers will install
restrictions, such as adjustable dampers, in branch ducts to create the proper
resistance. Others use different diameter ducts to vary the resistance of
each branch. Whatever technique is used, the important thing is, does it
work? Does the system provide for sufficient air flow at all hoods to capture
the contaminants?
Maintaining duct transport velocities is not a major problem with surface
coating operations, since the principal pollutant, VOC, is in a gaseous form.
For this application, low transport velocities are common and acceptable.
Again, as long as the entire system captures the contaminant at the hoods,
then specific system parameters, such as duct velocities and pressure drops
are not critical and need not be measured directly.
Since these procedures assume that the ductwork network was properly
designed to begin with, then your main concerns will be limited to insuring
that nothing has been done to the network that would change the system
pressure drop and hence the system flow. These changes could include
additional branches that have been added to the system without a change in the
fan size; holes, rust, and/or bends in the ductwork that would add additional
friction and/or resistance to the system airflow; and a rerouting of the
original ductwork design that would result in more bends and/or transition
33
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TABLE 3-2. CHECKLIST FOR HOODS
PLANT XY2: INSPECTOR -J •
DATE
I. PROCESS
fi /,
'A. PROCESS LINE DESIGNATION _
— -j
B. PROCESS EQUIPMENT CONTROLLED BY HOOD
C. PROCESS IN OPERATION DURING INSPECTION? YES Jj/ NO
D. 1. PROCESS OPERATING AT MAXIMUM CAPACITY? YES V NO
2. IF NOT, AT APPROXIMATELY WHAT PERCENT OF CAPACITY? %
II. HOOD
A. TYPE OF HOOD: ENCLOSURERECEIVING
CAPTURE \S OTHER (DESCRIBE)
B. 1. IS THE HOOD STRUCTURALLY SOUND? YES V* NO
2. IF THERE ARE HOLES, DENTS, ETC., WHERE ARE THEY?
C. 1. DOES THE HOOD HAVE A FILTER? YES \/ NO
2. WHEN WAS IT LAST INSPECTED?
III. GENERAL OBSERVATIONS
A. ARE THE VOC EMITTED AT A NOTICEABLE RATE? YES V NO
LAST CHANGED? //Sf\tlt'
B. ARE THERE CROSS-DRAFTS IN THE ROOM? YES y NO
C. IS THE HOOD WELL POSITIONED TO CAPTURE THE VOC? YES V NO
D. WHAT IS THE APPROXIMATE DISTANCE FROM THE EMISSION POINT TO
THE HOOD OPENING? "3 FT Q INCHES
E. 1. DOES THE HOOD APPEAR TO HAVE BEEN MODIFIED OR ALTERED IN
ANY WAY? YES NO
TO HA\
2. IF YES, HOW?
(continued)
34
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TABLE 3-2 (continued)
F. 1. DOES THE HOOD CAPTURE THE VOC? YES NO
2. IF NOT, WHAT IS HAPPENING WITH THE VOC?
G. 1. IS THERE AN ODOR IN THE ROOM? YES _y£
2. IF SO, WHERE? " ~ * "
NO
3. DOES IT SEEM TO BE RELATED TO THE HOOD CAPTURE EFFICIENCY?
YliS V NO
H. OBSERVATIONS
IV. MEASUREMENTS
A. TYPE OF INSTRUMENT USED
B. WHERE WAS MEASUREMENTS) TAKEN? (DRAW SKETCH BELOW)
C. INSTRUMENT READING(S) (IF APPLICABLE)
D. OBSERVATIONS
V. SKETCH PROCESS, LOCATION OF HOOD, POSITION OF MEASUREMENT DEVICE
VI. GENKRAL COMMENTS:
35
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pieces and hence more system resistance. The easiest way to inspect the
ductwork is to follow the individual branches from each hood. As ductwork
will often be installed overhead and is not easily accessible, use your own
judgment and only inspect what is practical to see up close. Check for holes
in the ductwork. Since the system is under a negative pressure, any hole will
cause room air to be sucked into the hole and may cause an audible noise.
There will be no obvious emission to signal the existence of a hole, so a
careful inspection is required. A hole will result in room air and not
contaminated VOC-laden air being sucked into the system. If the hole is
large, the VOC will not be captured at the hood, and as has been stated, the
capture of all pollutants at the hoods is the real test of how well a capture
and control system works. Nonetheless, if a hole is discovered, point it out
to your plant escort. It should be fixed as soon as possible to prevent it
from becoming worse. Also, try and see what caused the hole in the first
place. If it was due to an accidental puncture, then accidents happen and it
is hard to completely eliminate them, but if it was due to the position of the
ductwork in a busy area, or to the deterioration of the ductwork resulting
from condensation or excessive heat, then a long term remedy must be sought.
This aspect of the inspection requires some investigative cause and effect
thinking and some common sense. The problem must be understood and whatever
action necessary taken to insure that it does not happen again.
Ductwork inspections should pay particular attention to areas where
problems may show up, such as bends, transition pieces and dampers. Due to
the action of the moving, contaminated air, these pieces may see extra wear
and tear, and must be thoroughly checked for obvious signs of corrosion and
general deterioration. If a manual damper is installed, ask about how, when,
and why it is moved. Is it adjusted depending on which surface coating line
is in use? Or has it been placed in one position and never touched?
Whichever method is employed, the damper should be clearly labeled with
instructions on who is to be notified when it is adjusted. An out-of-position
damper can throw an entire capture system out of balance with disasterous
effects on the capture efficiency.
Because ductwork systems contain no moving parts, they may have been
forgotten and never checked by plant personnel. An inspection conducted as
part of an overall capture and control system inspection will serve to uncover
any unexpected deterioration in this area. Table 3-3 is a checklist for
ductwork which lists the principal items that must be addressed in a ductwork
inspection. You should complete one for each ductwork inspection. A copy of
this checklist is also included in Appendix C. A table which summarizes some
problems that may arise with ductwork and the effects that these problems
would have on operations or emissions can be found in Appendix D (see Table D-2),
3.2.1.4 Fans-
After the hoods, fans are the most important part of the capture system.
The fan generates the suction in the system that draws the contaminated air in
through the hoods. If the fan is too small, or operating too slow, the
airflow will be too low. Fortunately, fan selection does not always have to
be perfectly accurate; fans have some built-in flexibility since their
capacity increases with higher fan speeds and the speed is adjustable with
certain fan designs.
36
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TABLE 3-3. CHECKLIST FOR DUCTWORK
PLANT A 7 gT INSPECTOR
DATE
I. SYSTEM IJWOUT
A. 1. SKETCH BELOW THE WAY IN WHICH THE DUCTWORK TIES TOGETHER THE
HOODS AND THE CONTROL EQUIPMENT.
2. LAURL INDIVIDUAL BRANCHES.
ft. HOW MANY HOODS ARE CONNECTED TO THE DUCTWORK?
C. 1. ARE ALL HOODS CURRENTLY IN USE? YES \/ NO
2. IF NO, MARK UP SKETCH TO SHOW WHICH ARE/ARE NOT CONNECTED.
I). PHYSICAL INSPECTION
1. WHICH BRANCHES DID YOU INSPECT? (LIST)
2. NOTE THE APPEARANCE OF ANY BRANCH WHICH APPEARS TO BE IN POOR
CONDITION (DENTS, RUST, HOLES, ETC.)
3. NOTE THE NUMBER AND CONDITION OF ANY BENDS, ELBOWS AND TRANSITION
PEKCES WHICH ARE IN POOR CONDITION
4. DO ANY PIECKS OF DUCTWORK APPEAR NEWER THAN OTHERS?
YES V^NO (IF YES, NOTE WHERE ON SKETCH)
5. WHY WAS DUCTWORK CHANGED?
6. DO ANY SECTIONS OF THE DUCTWOKK APPEAR VULNERABLE TO BEIN£ HIT
BY A MOVING CART, FORKUFT, CRANE, ETC.? YES NO _V[ (IF
YES, NOTE ON SKETCH)
7. HOW OFTEN ARE DUCTS INSPECTED FOR MATERIAL (POLYMERS,RESINS,
ETC.) BUILDUP ON THE INSIDE? / PER Ja
(continued)
37
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TABLE 3-3 (continued)
E. DAMPERS
1. ARE DAMPERS USED TO ISOLATE DUCTWOIIK BRANCHES? YES • NO
2. WHERK ARK THE DAMPERS LOCATED? (NOTE ON SKETCH)
3. WHAT IS EACH DAMPER'S FUNCTION? EMERGENCY BYPASS
FLOW CONTROL
OTHER (SPECIFY)
IS DAMPER MANUALLY OR AUTOMATICALLY ACTIVATED?
5. WHAT IS THE POSITION OF EACH DAMPER DURING THE INSPECTION?
(0 DEGREES = FULL OPEN, 90 DEGREES = FULL CLOSED) ^O
_
6. IS EACH DAMPER CLEARLY LABELED? YES NO
LI. SKETCH OF SYSTEM
III. GENERAL COMMENTS:
38
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There are several different types of fans and each has its own relative
advantages and disadvantages. Axial fans are generally used to move large
quantities of air against very low static pressures, while centrifugal fans
are often used in industrial applications to move dust and fume laden air.12
Regardless of fan design, the volume and the fan static pressure are the two
most important items for proper fan selection.
The volume required by the system is that volume which will provide for
adequate capture velocity at all collection hoods. This is set by the number
of hoods in the system and the volume of air required at each. The static
pressure required by the fan is equal to the total resistance of the entire
capture and control system, since the fan must overcome this resistance to
deliver the required air volume. A fan is, therefore, chosen that delivers
the required volume at the required static pressure. As it turns out, the
volume and static pressure of any fan are inversely related. That is, as the
volume of air moved by the fan increases, its static pressure decreases and
vice versa. The exact way in which volume and pressure are related varies
with each fan. This means, however, that if you increase the fan volume too
much you may no longer be able to overcome the resistance of the system, so
there is a practical limit as to how much extra flow a fan can put out and
still be effective. What is also important is that, as the system resistance
increases, the volume of air moved by the fan decreases. -If this happens, the
face velocity at each collection hood will decrease, and the VOC emitted may
not be captured at the hoods. The increase in system resistance may take
place slowly, over a number of months or years, so the decrease in hood
capture efficiency may not be noticeable to plant personnel. However, this
decrease can happen and it is an item you should be concerned about during
your inspection.
Most fans you encounter in a plant will be one of two types: direct
driven or belt driven. Direct driven fans are connected directly to the
electric motor that drives them. They offer a more compact assembly and
assure constant fan speed as they eliminate belt slippage that does occur when
belt driven fans are not maintained. Fan speeds are limited to available
motor speeds however, and this makes them very inflexible. Certain direct
drive fans utilize an adjustable, transmission-like, linkage to provide some
amount of adjustment. The fan is still directly linked to the electric motor
and to change the fan speed you must change the linkage setting. Belt driven
fans are connected to their electric drive motor by means of a belt. This
belt gives them the flexibility of a quick change in fan speed without the
need to change the electric motor. For this reason belt driven fans are
preferred in ventilation systems. The fan speed can be adjusted to account
for changes in the number of hoods, or the total air or pressure requirements
of the system. The volume of air delivered by a fan is directly proportional
to the fan speed; double the fan speed and you double the output volume. Belt
driven fans enable plant personnel to adjust the volume of air they need by
adjusting the fan speed. However, the electric power consumption increases at
a much faster rate than the fan speed, so it is important for plant personnel
to closely match fan speed with exact air flow requirements.1--*
39
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Fans are the only part of the capture system that have moving parts.
Unlike hoods and ductwork, they require regular inspection, lubrication and
maintenance if they are to perform as designed. Your inspection of this part
of the system must, therefore, insure that the fans are working well now, that
they are regularly maintained and that they show no signs of neglect or lack
of maintenance. Check the fan before the motor. Inspect the fan wheel and
housing for wear and dust buildup. If possible, observe the fan wheel
rotation. It should spin freely with no vibration. Any detectable vibration
may indicate a dust buildup on the fan blades, misalignment of the fan and
electric motor, or a fan bearing problem. Dust buildup shouldn't be a problem
since VOC are gaseous, but check none-the-less. A misalignment problem may be
due to improper installation. A fan bearing problem may be caused by
misalignment, failure to lubricate the bearings regularly, or a fan belt that
is too tight. Bearings will usually overheat before they fail completely, so
if you can do so safely, feel the metal housing surrounding the bearing. If
it is hot to the touch, it may indicate a problem. Remember you are not here
to tell the plant people how to maintain their equipment, you are trying to
locate potential problem areas before they cause equipment breakdowns and
result in uncontrolled VOC emissions.
Next check the tension of the drive belt. Much like a car fan belt, it
should be tight, with a minimal amount of deflection. Slippage by the fan
belt will cause the fan to turn slower and hence pull less air. Conversely,
if the fan belt is too tight, it may cause a bearing failure. If the fan is
not running, closely inspect the belt for cuts and abrasion that may shorten
its life. The plant personnel should regularly inspect the fan belt for wear
and tear so that they can replace the belt before it breaks completely. Make
note of their fan belt inspection schedule.
Finally, check the motor. Put your hand on the motor casing, it should
be warm, but not hot to the touch. An overheated motor may also be due to a
bearing that is beginning to fail. Request the maintenance schedule for the
fan, the fan belt and the motor. The motor bearing should be greased on a
regular schedule, usually once per month or once every other month. All
moving parts eventually wear down and must be renewed or replaced. The more
frequent a moving part is inspected and lubricated, the longer it will last.
Note when the motor was last changed and if a spare is kept in stock. Also
see if a spare fan belt and fan art; maintained in inventory. While there may
be no regulatory requirements for spare parts, this information can give clues
as to the seriousness of the plant toward equipment operation and
maintenance. In general, plant personnel should be encouraged to maintain
spares of items such as fan belts and bearings that are not extremely
expensive. Such spares will minimize the down time of the capture and control
equipment should an equipment breakdown occur. The checklist in Table 3-4
presents important items that must be checked during a fan inspection. A
table which summarizes some problems that may arise with fans and the effects
that these problems would have on operations or emissions can be found in
Appendix I) (see Table D-3).
In summary, inspection of a capture system for surface coating VOC
emissions is not extremely difficult since the only moving parts are the fan
and its associated electric motor. This inspection, however, does require a
conscientious, thorough look at every hood, and every branch network of what
40
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TABLE 3-4. CHECKLIST FOR FANS
PLANT
1. TECHNICAL DATA
A. FAN MOTOR
1. MANUFACTURER
INSPECTOR
DATE
b.
c.
2.
RATED HORSEPOWER 7*5" 3. MAXIMU1
DRIVE
1. DIRECT BELT V OTHER
2.
FAN
1.
2.
PULLEY REDUCTION /•'/
MANUFACTURER
INSTALLATION DATE 3/~?b 3. 1
OPERATING AND MAINTENANCE DATA
NO
A. FAN MOTOR
1. NOTICEABLE OVERHEATING? YES
2. HOW OFTEN IS BEARING INSPECTED? ,
3. BEARING LAST CHANGED (DATE) i/S'/
PER
4. SPARE BEARING KEPT IN STOCK? YES
5. COMMENTS
B. DRIVE
1. AUDIBLE BELT SLIPPAGE? YES
2. BELT CONDITION
NO
NO
(continued)
41
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TABLE 3-4 (continued)
3.
4.
5.
6.
C. FAN
1.
2.
3.
4.
5.
6.
7.
8.
9.
HOW OFTEN IS BELT INSPECTED?
WHEN WAS BELT LAST CHANGED?
SPARE BELT IN STOCK? YES
COMMENTS
LAST ADJUSTED?
NO
NOTICEABLE FAN VIBRATION?
FAN BLADE CONDITION
HOW OFTEN IS BEARING INSPECTED?
BEARING LAST CHANGED
/
PER
SPARE BEARING KEPT IN STOCK? YES
DAMPER INSTALLED AT FAN INLET? YES
DAMPER POSITION % OPEN
FAN STATIC PRESSURES: INLET
NO
NO
V
CONTINUOUSLY MEASURED VARIABLES?
a. FAN SPEED YES
b. Alk FLOW RATE
c. INLET STATIC
PRESSURE
d. OUTLET STATIC
PRESSURE
YES
YES
YES V
OUTLET
NO
NO
"3 P±\-
NO
NO
III. GENERAL COMMENTS:
42
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can be a large and complex ductwork system, depending on the plant size and
the number of individual surface coating stations. The most important aspect
of the inspection is insuring that the VOC are captured by the hoods as they
are emitted. Proportionately more time and effort should be spent inspecting
the individual hoods. If a VOC capture problem is detected here, then the
rest of the inspection should be spent attempting to determine the cause of
the problem—is it the type and position of the hood? The physical condition
of the ductwork? Or the speed and condition of the fan? A problem in only
one branch of an entire duct network can usually be traced to that ductwork
and/or its damper. If no problems at all are encountered, then the remainder
of the inspection can be devoted to insuring all systems are tight and well
maintained.
3.2.2 Control Devices
3.2.2.1 Introduction—
A surface coating operation emission control system is comprised of two
portions; the emission capture system and the emission control device.
Capture systems, their various components, and inspection procedures are
discussed in Subsection 3.2.1. During your inspection of the hoods, ductwork,
and fans associated with the capture system, you will have undoubtedly noted
the location of the control device. This subsection describes the control
devices you are likely to encounter during inspections of surface coating
process emission control systems and provides procedures for conducting a
thorough evaluation of the operation and maintenance of these control devices.
Control devices applicable to coating operations include:
• carbon adsorbers,
• incinerators,
• condensers, and
• absorbers.
The type of control device used is often a function of VOC vapor stream
properties, such as:
• organics type and concentration,
• temperature,
• flow rate,
• humidity, and
• particulate concentration.
43
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Adsorbers, especially carbon adsorbers, and incinerators, both
direct-flame and catalytic, are the most frequently installed control devices
in add-on control systems for the reduction of VDC emissions at surface
coating facilities. These devices are, therefore, thoroughly discussed in
this subsection. Condensation and absorption devices can also be used to
control VOC emissions from surface coating processes. However, relatively few
of these devices have actually been installed at surface coating facilities.
Carbon adsorption can be used to reclaim solvents from the vapor phase
for reuse in a coating process. Adsorption is feasible for low temperature,
low particulate concentration vapor streams which contain single solvents.
Incineration is a method of oxidizing the VDC. Two types of incinerators
are used to control coatings emissions; direct-flame and catalytic.
Direct-flame incineration involves heating a vapor stream close to its
combustion temperature and then igniting the vapor in an afterburner.
Catalytic incineration makes use of a catalyst bed to allow combustion at
significantly lower temperatures. Organic materials are adsorbed on the
catalyst surface resulting in higher concentrations and subsequently faster
combustion.
Condensers consists of refrigeration units in which vapor streams are
chilled to a temperature below the VOC condensation point. Absorbers rely on
the principles of selective solubility. Vapor containing organic solvents is
passed into a tower countercurrent to a liquid solvent stream. The liquid
absorbs the organics and passes out of the column. The solvent must then be
thermally stripped of the dissolved organics before reuse.
When reviewing the suggested procedures for inspecting these control
devices, you should keep j.n mind the safety precautions noted earlier. The
chances of being exposed to extreme temperatures or high concentrations of VOC
are much greater near the control device than anywhere else in the control
system. Although a procedure may use the word "feel," it does not necessarily
imply "touch." If you are checking for extreme hot or cold, you can "feel"
the heat, or lack thereof, simply by placing your hand close to the equipment
without actually touching it. Likewise, when checking for "smell," don't put
your nose (and therefore your face) in the direct line of an exhaust or
emission source. Rather, start about an arm's length away and try to "wave"
the air around the source toward your nose with your hand or a notebook or
clipboard. If you must get closer, do so slowly, making sure that you won't
be "surprised" by a strong odor or high temperature.
3.2.2.2 Incinerators—
Due to their versatility in handling all types of VOC at a broad range of
concentrations, incinerators have gained widespread use for control of VOC
emissions in the surface coating industry. These devices are sometimes called
afterburners. Incinerators destroy the VOC by thermally oxidizing the
combustible organic vapors to water vapor and carbon dioxide. This complete
combustion process is usually assisted by the addition of an auxiliary fuel,
such as natural gas.
44
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Gaseous or fume incinerators, of the type used to oxidize VDC vapors, are
simple and straightforward. Most resemble cylindrical chambers with the VOC
vapors and auxiliary fuel fed into one end, and the hot combustion gases
exiting the other. Some units use separate burners for the VOC vapors and the
auxiliary fuel while others mix the two streams in one burner. Often the VDC
vapors are preheated by passing them through a heat recovery section located
in the hot (outlet) end. If you are unsure of the exact configuration, ask
for en explanation of the flow of the VOC into and out of the incinerator.
Gaseous or fume incinerators come in two basic types: direct flame and
catalytic. Direct flame units rely on high temperatures, in the 1200-1500°F
range, to oxidize the VOC.^ To reach these high temperatures, direct flame
incinerators burn substantial amounts of auxiliary fuel. In addition, the
entire incinerator system must be built stronger than catalytic types to
withstand these high temperatures. Catalytic incinerators, on the other hand,
operate at much lower temperatures, usually in the 500-900°F range.^ Oxidation
of the VOC in these units is carried out on the surface of the catalyst. A
catalyst is a material which changes the rate of the reaction but is not
consumed in the process. Commercial catalysts used for the incineration of
gaseous mixtures usually consist of platinum and paladium in small quantities
on some type of alumina support. This support may take the form of a
honeycomb, spheres, short rots, etc., which provide a large surface area in a
relatively small volume on which the VOC can burn.^ The catalyst system has an
advantage over direct flame incineration in that it operates at lower
temperatures and thus saves fuel. However, the catalyst may be expensive, it
has a usual life span of 3 to 5 years and is subject to fouling by a variety
of chemicals as well as dust and dirt. Its effectiveness in oxidizing VOC
emissions is reduced as the catalyst becomes fouled and/or is gradually
deactivated. There is no "best" incineration system and the selection of a
direct flame versus a catalytic incinerator is usually a personal and/or
economic choice.
The effective incineration of any solid, liquid or vapor, such as VOC,
requires that the three T's of combustion, Temperature, Time and Turbulence,
be met. The temperature at which the incinerator operates must be high enough
to completely oxidize the VOC. Once this temperature is known, it is set on
the incinerator control panel. If the incinerator temperature falls below
this point, auxiliary fuel is combusted to increase the temperature. The
minimal acceptable incinerator temperature will usually be set in the
operating permit. Make sure you know this temperature before you visit the
plant, and verify that the incinerator is operating at least at this
temperature for it is the single most important variable that affects
incinerator performance.
The time the VOC spends in the high temperature incinerator environment
is called its residence time. This time must be long enough to allow all of
the VOC to completely combust. If the residence time is too short, then some
of the VOC may pass out of the incinerator without being burned. Residence
time is designed into an incinerator by the design air flow rate and the
volume of the incinerator chamber. The only variable here is the air flow
-------
rate and it can only change if the fan speed changes. Too much air flow will
decrease the residence time while too little will increase it. Your
inspection uhould insure that the fan is operating as it was designed and
approved by your agency, and not any faster, for this could lead to VOC
emissions.
Finally, turbulence is important in incineration systems to insure good
mixing of the VOC, the combustion air and the auxiliary fuel. Good mixing is
required so that each molecule of VOC is contacted with oxygen for
combustion. If turbulence is insufficient, then some VOC may pass through the
incinerator without being burned. Turbulence is applied to an incinerator by
the action of the combustion air, the VOC and the auxiliary fuel as they are
injected into the incinerator at the burners. It is not easily checked, but
will only vary if any of these flows change dramatically.
Both direct flame and catalytic incinerators are components of an entire
incineration system which includes auxiliary fuel, combustion air and VOC feed
systems, auxiliary gas or oil burners, combustion control equipment, the
incinerator combustion chamber, its refractory lining, and a heat exchanger
(if installed). This system is presented graphically in Figure 3-4. Your
inspection must cover all of these items, since a failure in airy subsystem can
affect the ability of the entire incineration system to completely combust the
VOC vapors. A review of the individual subsystems will help point out
potential problems that may arise.
Air Supply Fan—This fan supplies the air needed for combustion of the
auxiliary fuel and/or the VOC. Its function may be combined with the
auxiliary fuel and/or the VOC feed lines. Too much air supplied to the
incinerator is inefficient and will result in shorter retention times and
potentially cause incomplete combustion of the VOCs, while too little air will
give longer retention times but may affect the air/VOC mixing and cause
localized pockets of oxygen starvation. You need to check the same items
mentioned for fans in the capture system. These include material buildup
and/or coating of the fan blades, excessive fan vibration, looseness of the
fan belt, material integrity of the fan blades and metal casing, overheating
of the electric motor and fan, and motor or fan bearing problems.
VOC Vapor Supply—This is the chief line of concern since it carries the
VOC to the incinerator. Leaks in this system will dilute the VOC stream,
increase the flow rate and decrease the incinerator efficiency. First check
the structural integrity of the ductwork. Look and listen for leaks at the
joints and connections. If a filter is installed on this supply line, check
when it was last replaced and/or inspected. A separate burner or "gun" may be
used to atomize the VOC feed. If possible, check this VOC burner for wear and
corrosion. If pressure and/or temperature gauges are installed in the VOC
line, record these readings. Ask for and inspect these readings for the last
several months. Look for noticeable changes in these measurements and
question plant personnel if a wide fluxuation is noticed. Such changes may be
early indications of equipment problems and should be addressed before they
cause equipment failures.
46
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CONTROLS
EXHAUST
GASES
TEMPERATURE
MEASUREMENTS
FLOW
RATES
STEEL SHELL
COMBUSTION
AIR
/ / / / s / / s s s s s s
COMBUSTION
CHAMBER
VVOC FEED
S / S///////SSSS
REFRACTORY
LINING
AUXILLIARY '
FUEL FEED
HEAT EXCHANGER
FROM
SURFACE COATING
OPERATIONS
Figure 3-4. Typical incinerator system.
-------
Gas and oil (auxiliary fuel) burners—These systems feed auxiliary fuel,
as required, to the incinerator to maintain minimum combustion temperatures*
Problems in this area can cause insufficient auxiliary fuel delivery and
incomplete fuel combustion. This in turn may lead to low incinerator
temperatures and low VOC destruction efficiency. Auxiliary fuel burner tips,
especially fuel oil tips, must be inspected for wear and corrosion. The
inspection, cleaning and maintenance schedule should be noted and the date of
the Last burner tip replacement recorded. Gas burners usually require little
maintenance. Oil burners are more susceptible to wear, pitting and corrosion,
due to the sulfur compounds in the fuel, and are usually serviced and/or
cleaned once per week. Note the specific cleaning cycle. The fuel oil supply
pump, strainer and/or filters must be inspected for leakage and plugging.
Fuel supply pump seals will periodically wear and need replacement. An
inspection of the operating logs for the auxiliary fuel system should also be
conducted, and discrepancies noted between current and past readings.
Incinerator controls—Most VOC incinerators are automatically
controlled. Once turned on, they will go through a preset startup cycle that
purges the system with clean air before auxiliary fuel is fed and ignited.
Once the unit reaches operating temperature, the VOC vapor stream feed
commences. The number and type of incinerator control parameters that are
constantly measured and/or recorded will vary from unit to unit. At a
minimum, the incinerator operating temperature should be measured and
recorded, since this is the only way relative incinerator compliance can be
checked on a regular basis. This temperature measurement should be compared
with limits set forth in the operating permit to insure the unit is operating
as originally approved. Temperature charts for the previous 6 months or since
the last inspection should be inspected to insure that the unit maintained its
proper temperature range, to note any month by month temperature variations,
and to see if the incinerator was operated at all times when the process was
in operation.' Any inconsistencies uncovered by these checks should be noted.
Since there are a wide variety of mechanical and electrical controls
commercially available, it is impossible to list specific operating and
maintenance instructions for each. The specific O&M instructions that are
included with the control panel O&M manual should be followed. Plant
personnel should be asked to review O&M procedures for the control panel, such
as how often the instruments are calibrated, how often they are cleaned and
what type of periodic maintenance, such as lubrication, is regularly conducted.
Refractory—The combustion chamber of the incinerator is normally lined
with refractory brick. It acts as an insulation material to prevent the metal
body of the incinerator from overheating and warping. If the refractory
failo, local hot spots will develop on the surface of the incinerator and this
may cause localized metal failure. Refractory is usually inspected once per
year, when the incinerator is shut down for annual maintenance. Note the date
of this last inspection. Closely inspect the outside of the combustion
chamber for telltale signs of refractory failure, such as blistering and/or
peeling paint. Check for warpage of the metal surfaces. Insure that all
metal to metal joints and connections mate evenly. A hot incinerator surface
can be a health and safety risk to the plant operators as well as an early
indication of refractory failure.
48
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Catalyst—The use of a catalyst enables catalytic incinerators to be
operated at temperatures much lower than direct flame units. However,
catalysts have a limited life time and, as they deteriorate, the ability to
reduce VOC concentrations decreases. "Poisoning" of the catalyst is due to a
number of factors, including chemicals which combine with the catalyst, such
as chlorine, fluorine, zinc and lead; masking agents which inhibit the
oxidation reactions, including halogen and sulfur compounds; and fouling
agents which coat and foul the catalyst, including patticulate, oils, carbon
and iron oxides. The exact condition of a catalyst can only be judged by a
direct physical inspection. Since its condition affects its ability to reduce
VOC emission, the catalyst must be inspected by an individual knowledgeable in
this area and it must be replaced when it shows signs of deterioration. Find
out when the catalyst was last replaced, when it was last inspected and who
conducted the inspection. Ask about the condition of the catalyst during this
inspection—Did it show signs of plugging, fouling or general deterioration?
Was it cleaned or altered? What are the company's plans for replacing the
catalyst? If any system variable is measured and recorded downstream of the
catalyst, such as stack temperature, review the records for this variable and
note any gradual change which may indicate a slow deterioration of the
catalyst. Since the catalyst is the single most important item in catalytic
incineration systems, close attention must be payed to how and when the
catalyst is inspected and maintained.
Heat Exchangers—Many incinerators recover the heat generated in
incineration through the use of heat exchangers located at the end of the
combustion chamber. These exchangers can be used to heat any one of a number
of air and/or water streams. The most common use of a heat exchanger in a VOC
incinerator installation is for preheating of the VOC feed stream. This
raises the VOC vapor stream temperature close to its ignition temperature and
minimizes the amount of auxiliary fuel required for combustion. A breakdown
of the heat exchanger can cause the release of unburned VOC by allowing the
VOC feed stream to enter the incinerator exhaust, thereby bypassing the
incinerator. The physical integrity of the heat exchanger is the most
important item that must be checked. The surface of the heat exchanger, and
all points where metal is joined by welds, rivets, flanges, etc., must be
closely examined. If inlet and/or outlet VOC temperatures are continuously
measured and recorded, an examination of this data over several months will
indicate unusual fluctuations. Such temperature changes may indicate slow
leaks in the system and bypassing of VOC directly iuto the rear of the
combustion chamber and out of the stack. Similarly if the differential
pressure across the heat exchanger is measured, fluctuations in this reading
may give an early indicate of problems. If such a fluctuation is noticed,
plant personnel should be questioned about the frequency of the inspection
schedule for the exchanger. It may not be frequent enough and it may not be
detailed enough to uncover the problems of leaks and/or holes in the metal
surfaces.
The incinerator and all subsystems may be running without problems when
the inspection is made. Hopefully this will be the case. The inspection will
insure that this condition remains the same by uncovering telltale signs of
49
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equipment deterioration. If a potential problem area can be noted and
corrected during normal plant maintenance shutdowns, then the VOC emissions
that result when an unexpected malfunction occurs can be avoided. Refer to
the checklist in Table 3-5 for an item by item description of those variables
that must be checked during an incinerator inspection. A table which
summarizes some problems that may arise with incinerators and the effects that
these problems would have on operations or emissions can be found in
Appendix D (see Table D-4).
3.2.2.3 Adsorbers —
Adsorption serves to concentrate solvent vapors for subsequent collection
or disposal. Organic vapor-laden exhaust air from a coating process is first
pretreated to remove materials which might inhibit efficient adsorber
operation. The air stream then passes through the adsorber itself; typically
a vessel (called a "bed") containing solid granules of adsorbent. Organic
vapors collect on the surface of the granules and the air passes out of the
bed. After a period of time, the adsorbent becomes saturated with organic
material and its capacity to adsorb additional VOC is substantially reduced.
At that time the vapor laden air is routed to a different bed containing
unsaturated adsorbent. The saturated bed is stripped of organic material (or
"regenerated") so that it can be used again. The organic material stripped
from the adsorbent is either recovered for reuse or disposed.
Figure 3-5 contains a flow sheet for a typical adsorption process.
Activated carbon is used extensively for adsorptive purposes because of its
high surface area to mass ratio. This enables the carbon to adsorb a
relatively large amount or organic vapors before it becomes saturated.
Efficient adsorption ot VOC is highly dependent on inlet vapor stream
conditions. If conditions are not appropriate, adsorption efficiency can be
substantially reduced. Key inlet vapor stream control variables include
temperature, humidity, pressure, and the presence of solids, liquids and high
boiling organic s.
Typical p re treatment steps
• temperature adjustment,
• humidity adjustment,
• pressure adjustment, and
• removal of undesired contaminants (e.g., entrained liquids,
entrained solids, high boiling organics).
Temperature Adjustment — Typical manufacturer's specifications call for
vapor stream temperatures below 100°F ( 38°C) at the inlet to the bed of
adsorbing material. High temperatures (e.g., trom curing oven exhaust) may
result in premature desorption, thermal degradation of components, hot spots
and bed fires. A cooler or heat exchanger is typically used to reduce stream
temperatures to within the design limits.
50
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TABLE 3-5. CHECKLIST FOR INCINERATORS
PLANT INSPECTOR
I. BACKGROUND DATA DATE
A. TYPE OF INCINERATOR: THERMAL CATALYTIC
B. MINIMUM ALLOWED TEMPERATURE ON OPERATING PERMIT O °F
C. OPERATING TEMPERATURE DURING INSPECTION °F
D. INSTALLATION DATE
/go
fT
II. AIR SUPPLY FAN
A. MAKE B. MODEL NUMBER
C. SPEED &QOO sV&f^ D. RATED FLOW RATE /£, OOP
E. FAN VIBRATION? YES NO I/
COULD NOT
F. MATERIAL BUILDUP ON FAN BLADES? YES NO CHECK
,
V
U. FAN BELT (IF USED) LOOSE? YES _ NO
H. FAN/MOTOR BEARING OVERHEATING? YES NO
V
I. BEARING INSPECTION SCHEDULE: / PER
J. BEARING LUBRICATION SCHEDULE: / PER
K. IS HIGH TEMPERATURE GREASE USED? YES Y NO
L. COMMENTS:
III. VOC SUPPLY
A. IS DUCTWORK STRUCTURALLY SOUND?
B. IS VOC PREHEATED? YES V NO
C. VOC TEMPERATURE: BEFORE PREHEATER g^5D /^AFTER PREHEATER 600
D. VOC PRESSURE: BEFORE PREHEATER AFTER PREHEATER —
(continued)
51
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TABLE 3-5 (continued)
IJ. 1. KILTER INSTALLED? YES _
2. FILTKK LAST INSPECTED?
NO
j/
F. 1. VOC BURNER: CLEAN? YES
WORN? YES
NO
NO
LAST CHANGED
COULDN'T
INSPECT
OOULDN1 T~
INSPECT
2. VOC BURNER LAST INSPECTED? 7/y/ LAST REPLACED?
/
Jbf
G. ADDITIONAL VOC MONITORING DEVICES? (LIST) % LE3~
H. COMMENTS
IV. AUXILIARY FUEL
A. TYPE: GAS
OIL
IF OIL, SULFUR CONTENT
B. FUEL DELIVERY PRESSURE?
C. 1. FUEL BURNER: CLEAN? YES
WORN? YES
NO
NO
COULDN'T
INSPECT
COULDN'T
INSPECT
2. FUEL BURNER LAST INSPECTED?
D. FUEL OIL SUPPLY PUMP CONDITION:
IL. 1. OIL FILTER: LAST INSPECTED?
F. COMMENTS :
LAST
v/
LAST REPLACED?
(continued)
52
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TABLE 3-5 (continued)
V.
VI.
.INCINERATOR CONTROLS
A. LIST EACH PARAMETER THAT IS CONTINUOUSLY MONITORED AND/OR RECORDED
AND ITS READING DURING THE INSPECTION
PARAMETER
READING
#30
B. 1. DOES INCINERATOR HAVE SHUTOFF CONTROLS FOR:
LOW TEMPERATURE?
FAN SHUTDOWN?
BURNER FLAME-OUT?_
HIGH VOC CONCENTRATION?
V
2. ARE THESE MANUALoR AUTOMATIC?
3. ANY ALARMS? YES V NO SPECIFY
/°L£L-
C. 1. CALIBRATION SCHEDULE FOR CONTROL INSTRUMENTS? YES V NO
2. LAST CALIBRATION OF TEMPERATURE RECORDER?
3. MAINTENANCE/LUBRICATION SCHEDULE FOR INSTRUMENTS?
—/-— -/—
A. WHO CONDUCTS THE CALIBRATIONS?
D. COMMENTS:
REFRACTORY
A. 1. TYPE OF REFRACTORY?
2. THICKNESS OF REFRACTORY:
INCHES
3. HOW OFTEN IS REFRACTORY CHANGED?
B. 1. DATE LAST INSPECTED? /
2. INSPECTED BY WHOM?
3. ANY PROBLEMS NOTED DURING INSPECTION?
£L
(continued)
53
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TABLE 3-5 (continued)
C. NOTICEABLE HOT SPOTS ON OUTER SURFACE OF COMBUSTION CHAMBER?
YES NO \X"
D. NOTICEABLE METAL WARPAGE? YES NO \f
E. METAL CONNECTIONS MATE EVENLY? YES ^ NO
F. COMMENTS:
VII. CATALYST
A. 1. CATALYST MATERIAL?
2. DEPTH OF CATALYST BED? /*{ INCHES
3. LAST INSPECTION?
4. INSPECTED BY WHOM? *___
7
5. CONDITION DURING INSPECTION?
I?
6. CATALYST CLEANING SCHEDULE / PER
7. HOW OFTEN IS CATALYST CHECKED FOR POISONING? / PER
8. BY WHOM?
9. DATE OF LAST REPLACEMENT?
10. IS SPARE CATALYST KEPT IN STOCK? YES y^ NO _
B. STACK TEMPERATURE MEASUREMENT? YES \/ NO _ IF YES:
C. COMMENTS:
Vtll. HEAT EXCHANGERS
A. SUBSTANCE PREHEATED (VOC, COMBUSTION AIR, WATER)
B. 1. INLET TEMPERATURE J-&0 °F
2. OUTLET TEMPERATURE 6>OQ°F
3. STACK TEMPERATURE / <^JJ °F
C. PHYSICAL INTEGRITY
(continued)
54
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TABLE 3-5 (continued)
X.
D. PLANT INSPECTION SCHEDULE
li. COMMKNTS:
PER
IX. A. IS INCINERATOR LOCATED OUTSIDE? YES
B. IS EXTERIOR CORRODED?
RUSTED?
V
NO
OPERATING LOGS
A. ARE OPERATING LOGS KEPT FOR:
AUXILIARY FUEL USAGE? YES
INCINERATOR CONTROLS? YES
CATALYST TEMPERATURES? YES
HEAT EXCHANGERS? YES NO
Y
NO
NO
NO
B. IF POSSIBLE, CHECK OPERATING LOGS FOR SIGNIFICANT DEVIATIONS FOR
SIGNIFICANT DEVIATIONS FROM DESIGN AND NORMAL OPERATING CONDTIONS
XI. SKETCH OF SYSTEM
XII. GENERAL COMMENTS
55
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Vapor-
laden
Air-
strfflm
V
X"
Fi
1 I
1 '
ter C(
Cooler
O
*-~s
Blower
Adsorber No.. 1
Adsorber No. 2
Low-pressure
Steam
Stripped
Air
->•
Condenser
Recovered
"Solvent
•Water
Decanter
Figure 3-5. Carbon adsorption process.
10
-------
Humidity Adjustment — Relative humidities of inlet vapor streams should be
kept within a specific range. If the relative humidity is higher than 50
percent, water vapor will compete with moderately adsorbable VOC for
adsorption sites, thereby reducing operating capacity. Very low relative
humidities (typically less than 20 percent) may result in excessive
temperatures in the bed; particularly when adsorbing solvents with high heats
of adsorption (e.g., ketones), therefore, the humidity must be regulated.
Typical methods for adjusting vapor stream humidity include heating, cooling,
or addition of dry dilution air. 16, 17
Pressure Adjustment — Adsorption beds are often designed to process large
volumes of vapor through a specific depth of carbon. In order to overcome the
pressure drop across the bed caused by frictional losses, a blower is usually
installed upstream of (before) the adsorption unit. The blower supplies the
necessary increase in vapor stream velocity to overcome pressure losses.
Removal of Contaminants — Entrained solids such as dust, dirt and lint
must be removed from adsorber inlet streams. Particulate matter can lodge on
the carbon and reduce its adsorbing capacity. Solids can also build up in
between pieces of carbon reducing vapor flow through the bed and causing
excess pressure drop. Devices for removing entrained solids include cloth or
fiberglass pref liters. Filters may be either reusable or throw
Entrained liquids include water droplets and condensed volatile
organics. Typical removal methods for entrained liquids include:
• mist eliminators (with cyclone or zigzag baffles) — used for large
droplets, or
• small mesh screens — used for small droplets.
High boiling organics should be removed to prevent fouling of the bed.
These compounds are difficult to desorb, thus reducing effective bed capacity
and carbon life. High boilers may also condense on the prefilter causing an
excessive pressure drop. Methods for removal of high boiling organics include
condensers and preadsorbers, such as a minibed with disposable carbon,
upstream of the main bed.
The adsorption unit serves to concentrate solvent vapors for subsequent
collection or disposal. As vapor-laden exhaust from a coating process passes
through a vessel containing adsorbent material, organic components are
captured at the surface of this material by physical or chemical interaction.
When a bed becomes saturated it reaches the "breakthrough" point. This means
that the concentration of organic vapors in the air stream exiting the adsorber
has reached an unacceptably high level. Exhaust from the coating process is
then routed to a parallel bed and the saturated bed is regenerated. 2> 6, 10, 16
Physical adsorption is achieved through intermolecular forces which
attract but do not bind molecules together. Chemical adsorption (or
chemisorption) is a result of the actual development of chemical bonds between
57
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adsorbent and adsorbate. Once these bonds are formed they are difficult
to break using conventional regeneration methods. Chemical adsorbent must
usually be discarded, resulting in potentially high operating costs. For this
reason, chemiaorption is not typically used at surface coating facilities.
Adsorbers can be classified as:^"
• regenerable,
• nonregenerable,
• fixed bed, and
• continuous.
Regenerable beds are those in which adsorbent capacity can be restored.
Regeneration of an adsorber usually involves injecting a heated medium (e.g.,
steam, air, inert gas) into a saturated bed and stripping organic vapors away
from the adsorbent.^ Another type of regeneration is vacuum desorption
which releases adsorbed organics by lowering their partial pressure.^°
Another less common method is thermal regeneration where the saturated bed is
heated to volatilize the adsorbed organics and the bed is subsequently purged
with inert gas or air.^° After a bed is regenerated, a residual amount of
organics is always left on the adsorbent. This residual is called the "heel."
Nonregenerable beds contain adsorbent which is discarded when it becomes
saturated. Nonregenerable and thermally regenerated beds are limited to use
in adsorption of low organic concentration streams or in odor control because
in these applications the adsorbent does not become saturated until after an
extended period.'-'
Fixed bed adsorbers are vessels in which the adsorbent remains stationary
and is either adsorbing, regenerating or drying and cooling at a given time.
Continuous beds are designed to adsorb, and regenerate at the same time.
Example of continuous adsorbers are fluidized beds and concentric beds.
Figure 3-6 depicts a fluidized bed adsorption vessel. In these beds saturated
adsorbent is removed from the working (adsorbing) section of the vessel to the
regenerating section continuously. The adsorbent is then desorbed, cooled,
dried and returned to the adsorbing section. *•'» *•*
Adsorbents can be regenerated in place or removed, regenerated and
replaced. Removable beds are typically small. Saturated adsorbent is picked
up by the supplier (vendor), heated in a kiln or furnace to drive off adsorbed
organics and returned to the coating facility.
After a bed has been regenerated it must be dried (particularly when
using steam regeneration) and cooled. Figure 3-7 shows the flow of
vapor-laden air, steam and purge air in a typical adsorption system. The
purpose of cooling and drying the bed is to reduce the water and heat content
of the bed which can affect adsorption efficiency. '
58
-------
ADSORPTtOU
SECTION
TUBE
RE.COVERE.D
50LVEWT
Figure 3-6. Fluidized-bed carbon adsorption system.
59
-------
X
VALVE
VAPOR-LADEN
EXHAUST GAS
RECYCLE
FLAME |
ARRESTER <- — —
V
TO RECOVERY
OR DISPOSAL
— _ — ___ ___. STEAM
— _ PURGE AIR
CLEAN GAS
TO STACK
Figure 3-7. Adsorption flow streams.
-------
Dry purge air (which serves as both a cooling and drying agent) is
typically blown through a recently regenerated bed. External cooling of the
vessel may also be performed. Purge air exiting the vessel is usually routed
to the other (adsorbing) bed.
Une cycle of an adsorption system, therefore, consists of three periods;
adsorption, regeneration, and drying and cooling. The amount of time allowed
for each of these periods varies widely among different applications.1°
Figure 3-8 presents the various possibilities of material flow in an adsorption
eyele.
AU:;<>xmo:!: DKSOBPTIOH- VAPOR KSMVKSY os DISPOSAL:
DKSOBPTIOH-
CllOICt OF:
V.ipor-Ljitlen
Air
('ondrns.i 11 on
Figure 3-8. Adsorbent regeneration and vapor recovery
- . ID
or disposal alternative
18
The most common type of adsorbent used for collection of organic vapors
is activated carbon. The carbon comes in several forms including granular,
palletized and powder. Other types of adsorbent media not commonly used in
collecting organic vapors include silica gel, activated alumina and molecular
sieves.1'il"i20
The number and configuration of adsorber vessels used in a particular
application is a function of air flow rate and cycle time. A minimum of
two parallel beds are required; one to adsorb while the other is regenerating,
cooling and drying. With three beds, one bed is adsorbing, one is
regenerating while the third is cooling and drying. Occasionally vessels are
run in series to ensure containment of breakthrough emissions. The initial
bed must then be regenerated more frequently than the secondary bed.
Adsorption vessels may be installed vertically or horizontally. Vertical
beds are used for low air flow rates and horizontal beds are used in high flow
applications. The inlet air stream to a vertical vessel should flow downward
from the top to reduce entrainraent of carbon particles in the outlet
stream.*' However, fluidized beds require that the air stream flow upward
so as to fluidize the adsorption bed.l*
As stated previously, adsorption of organic vapors is achieved through
physical interaction at the molecular level. Some solvents (e.g., ketones)
interact chemically with activated carbon. These interactions (hydrolysis,
oxidation, halogenation) can release substantial quantities of heat and
vessels may have to be externally cooled.17,19
61
-------
The effluent stream which exits the bed during regeneration consists of
vapor media (steam, inert gas, air) and desorbed organic vapor. Depending on
certain properties of the solvent (e.g., value, number of components,
miscibility) the effluent may either be recovered or disposed. If steam
regeneration is used the effluent stream is usually condensed and the
condensate is separated. If hot air or inert gas is used, the stream is
typically incinerated. Other methods of solvent recovery include absorption
(wet scrubbing), distillation and secondary adsorption.^^»^0 For more
information regarding absorption and condensation, see Subsection 3.2.2.4.
Subsequent to condensing, a water and solvent mixture is decanted or
distilled, depending on the miscibility of the solvent. Decanting involves
pumping the mixture to a tank where the liquid has time to settle and separate
into layers. Water and solvents are pumped out of the tank through separate
pipes. The water usually goes back to the boiler and the solvent back to the
formulation unit. Figure 3-9 shows the flow arrangement in a decanter.
Organic vapor may also be recycled to the working adsorber.
ATMOSPHERIC
VENT
CONDENSED
VAPOR
VENT
SOLVENT
TO
STORAGE
TO BLOWER INLET
FLAME ARRESTER
WASTE. WATER
OUTLET
LIQUID INTERFACE
Figure 3-9. Decanter for separating nonmiscible liquids.^
Distillation of the water/solvent mixture is performed if the solvent is
valuable and cannot be separated by simple decanting. Also, solvents which
have stringent purity requirements are distilled to remove contaminants. For
additional information on distillation operations see the Chemical Engineers
Handbook.
62
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Control systems are used to monitor and adjust process operating
conditions. Every control system consists of an instrument for measuring
process conditions and a control device for adjusting those conditions.
Examples of measuring instruments include:21
• thermocouples (temperature),
• manometers (pressure),
• floats (level), and
• flow meters.
Examples of control devices include:
• valves,
• dampers,
• heaters or coolers, and
• pumps or blowers.
The purpose of a measuring instrument is to monitor a specific process
parameter (e.g., temperature, pressure, flow rate). The instrument is preset
at a value (or range of values) for that parameter. If the actual process
value of the parameter deviates from the preset value the instrument signals
the control device. The control device then acts to change the process
condition in such a way as to return the process variable to its preset value.
Control devices can be either manual or automatic. Manual devices
require an operator to activate them. An example is an alarm which signals an
operator to adjust process conditions. Automatic control devices rely on a
signal from a measuring instrument to be activated. These signals are either
mechanical (usually pneumatic) or electronic.21
Measurement and control devices are especially important in adsorption
systems as they are often used to regulate the frequency with which the bed is
regenerated, based on the organic vapor concentration in the effluent stream.
When concentration levels reach the preset value corresponding to
breakthrough, the bed is regenerated. Another control technique for
regenerating saturated adsorption beds is the timed cycle. This method
assumes that a bed will reach the breakthrough point after it has been running
for a specific amount of time. A timer keeps track of how long the bed has
been running and signals for regeneration upon reaching the preset time.
Because the timed cycle method assumes a constant air flow rate through the
bed and a constant solvent concentration in the air stream, any deviation from
these assumed values can result in inefficient adsorber operation.22
Occasionally, both vapor concentration and timed cycle methods are used
simultaneously.23
63
-------
Organic vapor concentrations can be monitored at the inlet of an adsorber
as well as the outlet. This is frequently the case in systems with large
variations in inlet concentrations. If the concentration of organics is low
(i.e., lower than the emission limit for the facility), it can bypass the
adsorber and be vented directly to the atmosphere.22
The proper calibration of instruments used in control systems is crucial
to Liu- operation of an organic vapor collection system. If instruments are
not properly calibrated, measurements of process variables become inaccurate.
This in turn leads to faulty control of process conditions and potential
excess emissions.21
V While the carbon adsorption system may appear more complex and difficult
to understand than the other components of the capture and control system, it
should be inspected in a similar manner. Each subsystem must be examined
individually to insure it is working and maintained, as designed. Above all,
the inspector must have a thorough knowledge of what conditions were
established for the adsorber on the operating permit so that the field check
can verify the key operating parameters that were reviewed and approved by the
agency.
First check the physical exterior of the system for corrosion and
abrasion. If the metal surfaces are noticeably corroded, determine if this
deterioration is located in one spot or is equal across all surfaces. Spot
corrosion should be investigated a bit further, since it may be indicative of
a hot spot, or some similar localized condition within the adsorber, that is
due to the buildup of high organics concentrations and/or a reduced flow
rate. This external inspection will also serve to familiarize you with the
location of the other adsorber components such as the VOC supply line, the
blower motor and fan, the exhaust line, the steam feed line (if steam is used
for regeneration), and the piping arrangement used to alternate VOC feed
between multiple adsorber beds.
Next check the various feed systems into the adsorber. Inspect the VOC
line, looking for holes or corrosion that might allow leakage of room air to
dilute the VOC concentration. If this line has a prefilter to screen
particulates and other solids that would clog the adsorbent, determine the
condition of this filter. When was it last inspected? How frequently is it
cleaned and/or replaced and when was this done? Follow the VOC line to the
blower which pushes the VOC through the adsorber bed. The blower will consist
of an electric motor and a fan. Inspect the condition of the fan blades for
corrosion, erosion and buildup. Note any vibration of the fan. Inspect the
electric motor. Is the bearing overheating? When was the bearing last
inspected? Lubricated? Replaced? Is a spare bearing maintained in stock?
Remember a spare parts inventory is not required, but if you ask about spare
parts, it will show your concern and may prompt the facility to maintain key
items in reserve. At this time, check all valves, damper and cross
connections that allow the VOC to be vented to a second adsorber while the
first is being regenerated. Look for tight metal to metal connections, and
damper and valve positions. Is there a set operating schedule for switching
from one adsorber bed to another? Obtain a copy of this operating procedure
if you can.
64
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If steam is used to regenerate the adsorbent, inspect the steam feed
line, and the VOC/steam return line. The steam feed line should have a steam
trap and regulator to insure that excess moisture is removed before the steam
is used for regeneration. Excess moisture in the steam can cause a reaction
between water and hydrocarbons that may hasten corrosion of the adsorber
internals and its use should be avoided. Follow the VOC/steam exhaust line to
the condenser and associated organics/water decanter. Inspect both condenser
nn
-------
Finally, as part of your control system inspection, check the safety
devices used with the adsorber items, including flame arrestors, high bed
temperature shutdowns, and safety relief valves that are installed for the
safety of the workers and the protection of the equipment. Equipment
malfunction and/or poor operating procedures can cause the buildup of VOC in
excessive concentrations. This, in turn, can lead to potential fire and/or
explosive conditions within the adsorber. Verify the inspection schedule of
these safety devices and obtain the date of their last test.
The checklist in Table 3-6 details all of the inspection items that have
been discussed in this section. It should be used to record data collected
during any adsorber inspection. A table which summarizes some problems that
may arise with adsorption units and the effects that these problems would have
on operations or emissions can be found in Appendix D (see Table D-5).
3.2.2.4 Absorption and Condensation—
Two control methods which have found limited use in the control of VOC
trom coating applications are absorption and condensation.?''»*0
Subsequently, discussion of these methods is limited in this guide. Indepth
analyses of absorption and condensation unit operations are available in the
literature.
In gas absorption a soluble vapor (such as VOC) is absorbed, by means of
liquid in which the vapor is soluble. The vapor is typically carried through
the absorber by an inert gas. The solute (VOC) is subsequently recovered from
the liquid by distillation. Sometimes the solute is removed from the liquid
by bringing the liquid into contact with an inert gas. Such an operation, the
reverse of gas absorption, is desorption or gas stripping.^ Figure 3-10
depicts a typical absorption system with solvent recovery.
A common apparatus used in gas absorption is the packed tower, an example
of which is shown in Figure 3-11. The device consists of a cylindrical
column, or tower, equipped with a gas inlet and distributing space at the
bottom; a liquid inlet and distributor at the top; liquid and gas outlets at
the bottom and top, respectively; and a supported mass of inert solid shapes,
called tower packing. The inlet solvent is distributed over the top of the
packing by the distributor and, in ideal operation, uniformly wets the
surfaces of the packing. The solute-containing gas enters the distributing
space below the packing and flows upward through the interstices in the
packing, countercurrent to the flow of the liquid. The packing provides a
large area of contact between the liquid and gas and encourages intimate
contact between the phases. The solute is absorbed by the fresh liquid
entering the tower and dilute gas leaves the top. The liquid is enriched in
solute as it flows down the tower, and concentrated liquid leaves the bottom
ot the tower through the liquid out let. ^> "»^o
Many types of tower packing are available including rock, gravel, and
coke in various manufactured shapes. The most common type is Raschig rings,
which consist of hollow cylinders having an external diameter equal to their
length. Other shapes include Berl® saddles, Intalox" saddles, Pall rings,
llypak'"', and spiral-type rings. 19,25
66
-------
TABLE 3-6. CHECKLIST FOR ADSORBERS
PLANT fl. INSPECTOR
I. HACK GROUND DATA DATE
A. MANUFACTURER
15. INSTALLATION DATE
C. MAKE AND MODEL NUMBER
D. TYPE OF ADSORBER: FIXED \S CONTINUOUS
FLUIDIZED BED CONCENTRIC
OTHER (SPECIFY)
E. REASON FOR INSTALLATION OF ADSORBER: TO MEET EMISSION LIMITS?
TO REMOVE ODORS?
F. NUMBER OF BliDS
C. BEOS ARE: VERTICAL HORIZONTAL
II. TYPE OF ADSORBENT: THROWAWAY REGENERABLE \S
ACTIVATED CARBON \S
OTHER (SPECIFY)
1. FO'W OF ADSORBENT: GRANULAR Y PELLETIZED POWDER
J. WHIiRE IS ADSORBENT REGENERATED? ONSITE
OFF-SITE (SPECIFY)
K. GAS INLET STREAM DATA:
DESIGN DURING INSPECTION
FLOW KATE (CFM) <£OOQ / 90O
TEMPERATURE ( °F) oO^/O /iO
RELATIVE HUMIDITY
VOC VAPOR CONCENTRATION
(continued)
67
-------
TABLE 3-6 (continued)
L. NUMBER OF EMISSION POINTS VENTED TO ADSORBER JO
M. TYPE OF EMISSION POINTS VENTED TO ADSORBER
N. I'EKCENT VOC IN SURFACE COATING FORMULATION DURING INSPECTION
30%
0. SURFACE COATING APPLICATION RATE ^GAL/HlO LB/HR)
II. EXTERIOR CHECK
A. CORROS ION /ABRASION EVIDENT? YES NO V/
b. IF YES, IS IT LOCALIZED? YES _ NO
C. IF LOCALIZED, SKETCH ADSORBER/CORROSION AREAS BELOW.
III. VOC FEED
A. VOC CONTENT OF CAS STREAM ENTERING ADSORBER _
li. IS A PRE FILTER INSTALLED? YES NO \S
C. TYPE OF PREFILTEK. THROWAWAY FABRIC
D. LAST FILTER INSPECTION: REPLACEMENT:
IV. BLOWER
A. ' FAN
1. POSITION OF FAN: ADSORBER INLET V OUTLET
2. IS CORROSION EVIDENT? YES NO
.'1. IS EROSION EVIDENT? YES NO
A. IS BUILD-UP ON FAN BLADES EVIDENT? YES \S NO
3. IS VIBRATION EVIDENT? YES NO
6. INSPECTION SCHEDULE /
PER
(continued)
68
-------
TABLE 3-6 (continued)
li. MOTOR
\/
1. EVIDENCE OF OVERHEATED BEARING? YES NO
2. INSPECTION SCHEDULE / PER
3. LUBRICATION SCHEDULE
V. VALVES, DAMPERS
A. ARE ALL VALVES AND DAMPERS LABELED? YES NO
B. IF YES, SKETCH LOCATION AND DESIGNATION BELOW
C. IS THERE A STANDARD OPERATING PROCEDURE
(S.O.P.) FOR SWITCHING FROM ONE ADSORBER s
BED TO ANOTHER? YES V NO
I). CAN YOU OBTAIN A COPY OF THIS S.O.P.? YES NO
Vi. ADSORHANT REGENERATION
A. TYPE OF REGENERATION:
ftf -f&
INERT GAS (SPECIFY)
B. REGENERATION STREAM CONTROL DEVICE:
INCINERATOR ABSORBER
CONDENSER/DECANTER
SECONDARY ADSORBER
OTHER (SPECIFY)
(J. REGENERATION INITIATION METHOD:
L. VAPOR CONCENTRATION
Q)NCENTRATION LIMIT PPM
LOCATION OF CONCENTRATION
MEASUREMENT DEVICES OUTLET
MEASUREMENT DEVICES INLET
(continued)
69
-------
TABLE 3-6 (continued)
2. TIMED CYCLE
LENGTH OF TIME (HOURS)
ADSORPTION MIN
REGENERATION MIN
DRY ING/COOL ING MIN
TOTAL CYCLE TIME MIN
3. OTHER (SPECIFY) ^
/
D. IF STEAM REGENERATION IS USED:
1. HOW OFTEN ARE STEAM TRAPS BLED? PER
(continued)
2. STKAM PRESSURE PS I
VII. WKATHER PROTECTION
A. ADSORBER INSTALLED OUTSIDE? YES NO
B. ELKCTRIC HEATER UTILIZED? YES NO
C. FREEZE CONTROL THERMOSTAT UTILIZED? YES NO
D. OTHER WEATIIEK PROTECTION MEASURES? (SPECIFY)
VI11.ADSORBENT
A. 1. IS ADSORBENT REGULARLY INSPECTED FOR X
DETERIORATION? YES NO y
2. HOW OFTEN? PER
H. 1. IS MAKE-UP ADSORBENT ADDED TO THE
BED ON A REGULAR BASIS? YES _ NO
2. HOW OFTEN? _ PER _
3. HOW MUCH IS ADDED?
70
-------
TABLE 3-6 (continued)
C. 1. LS Tilt ADSORBENT REGULARLY
REPLACED?
2. HOW OFTEN?
IX. ADSORBER INTERNALS
YES
NO
PER
A. ARE THE INTERNALS LINED WITH A PROTECTIVE COATING? YES
B. HOW OFTEN ARE THEY INSPECTED? / PER
X
CLEANED? / PER
C. IS THE EXTERIOR WARPED DUE TO EXCESSIVE HEAT? YES
X. CONDENSED LIQUID
A. IF A CONDENSER/DECANTER IS USED, WHAT
IS DONE WITH NONCONDENSIBLES (I.E., THE
VAPOR EXITING THE CONDENSER/DECANTER)
NO \f
NO
D.
l>. WHAT IS DONE WITH THE CONDENSIBLES?
(I.E., DECANTED LIQUID)?
1. ARE TRANSFER PUMPS INSTALLED?
2. WHERE ARE THEY LOCATED?
YES
3. IS THE PUMP SEAL AND/OR THE PACKING
LEAK f.NG? YES
4. WHEN WAS SEAL AND/OR PACKING LAST
REPLACED?
1. IS PUMP BEARING OVERHEATING?
2. WHEN WAS BEARING LAST INSPECTED?
LUBRICATED?
REPLACED?
YES
(continued)
NO
NO
NO
71
-------
TABLE 3-6 (continued)
XI. CONTROLS
A. DOES FACILITY HAVE MONITORS AND/OR RECORDERS
FOR (SPECIFY READING)
PARAMETER MONITOR RECORDER READING
1. PRESSURE DROP ACROSS BED?
2. PRESSURli DROP ACROSS
PREFILTER?
3. VA1DR INLET TEMPERATURE? (°F) V^ 3^O
4. BED TEMPERATURE? (°F)
5. VAPOR OUTLET TEMPERATURE? (°F)
6. OTHER (SPECIFY)
7. OTHER (SPECIFY)
8. OTHER (SPECIFY)
XL1. SAFETY DEVICES INSTALLED
A. FLAME ARRESTOR YES NO _
H. HIGH BED TEMPERATURE SHUTDOWN YES NO
C. SAFETY RELIEF VALVE YES \ NO
I). OTHER
SAFETY INSPECTION SCHEDULE / PER
/
X11I.A. IS ADSORBER USED IN SERIES WITH OTHER CONTROL DEVICES?
YES V NO
B. WHAT KIND(S)
C. DRAW llliLOW THE SEQUENCE OF UNITS
(continued)
72
-------
TABLE 3-6 (continued)
XIV. SKKTCIl SYSTIW—-NOTING IMPORTANT DETAILS
73
-------
r
.1
y^
I -.c.ir. = -t£3
-.TS.'=^=.O *C-_V = ».iT
Figure 3-10. Absorption system with stripping tower (solvent recycled to absorber).
16
-------
Liquid_
inlet
Li quill distributor
Liquid^
outlet
Figure 3-11. Cross section of a packed tower for gas absorption.
75
-------
In contrast to packed towers, where gas and solvent are in continuous
contact throughout the packed bed, plate towers employ stepwise contact by
means of a number of trays or plates that are arranged so that the gas is
dispersed through a layer of liquid on each plate. Each plate is more or less
a separate stage, and the number of plates required is dependent on the
difficulty of the mass-transfer operation and the degree of separation
required.^
The bubble-cap plate is a common type of tray, and most general
references deal primarily with it in discussion of plate towers. Other types
of plates, including perforated trays and valve trays, may be used in new
installations because they are less expensive and their performance is about
equal to bubble-cap tray performance.16
A schematic section of a bubble-cap tray tower is shown in Figure 3-12.
Each plate is equipped with openings (vapor risers) surmounted by bubble
caps. The gas rises through the tower and passes through the openings in the
plate and through slots in the periphery of the bubble caps which are
submerged in liquid. The liquid enters at the top of the tower and then flows
across each plate and downward from plate to plate through down spouts. The
depth of liquid on the plate and the liquid flow patterns across the plate are
controlled by various weir arrangements.16
iHlU
IRtt
cr»ss°oui
1C(y
M IM
•] : r CIS OUT
•" ^
• • i i
RlNC !
LIQUID IN
' I •••.'.
i •••••'. •*••• I BUBBLE C«P
•.-•..^•vr.vtj ,
: • ii
; i. SIDISIPUM
'
PISE* '•',,-• • ' '• :NTIR».[|II»II
1 ' • ••' : I P FCED
TROTH ' '
i '••-.":"n
I :-!.• 1-7
-
ij
r
c«s IN
i ^47. T.~|v 11 QUID OUT
Figure 3-12. Bubble-cap tray tower.16
76
-------
Solvents used for absorption should exhibit the following characteristics:^-"
1.
-------
absorber column, any hole will cause solvent and/or VOC vapors to be pushed
out the hole. So look for liquid on the metal surfaces. Next ask plant
personnel about routine maintenance items. How often are the solvent spray
nozzles inspected and cleaned? Scale and particulate buildup in these nozzles
can clog them, resulting in an uneven solvent spray. This will decrease the
absorber efficiency and lead to increased VOC emissions. Now verify the
inspection and cleaning cycle for the absorber packing. Since particulate
build-up on the packing can decrease its effectiveness, there should be a set
inspection schedule. It should not need to be cleaned very often if the VOC,
solvent feed and solvent recirculation lines have filters and strainers, but
chuck the plant's maintenance schedule for this item none-the-less.
Finally, inspect the solvent recirculation line to see if strainers
and/or filters are installed. Such cleaning devices will minimize scale and
particulate build-up on all internal surfaces which come in contact with the
solvent. Strainers and filters should be inspected and cleaned or replaced on
a regular basis. Make note of this inspection and servicing cycle. Table 3-7
is a checklist which details the principal items that must be reviewed during
an absorber inspection. A table which summarizes some problems that may arise
with absorption units and the effects that these problems would have on
operations or emissions can be found in Appendix D (see Table D-6).
Condensation is an operation in which one or more volatile components of
a vapor mixture are separated from the remaining vapor by cooling the vapor
below the condensation temperature of the component to be recovered. In a
two-component vapor stream, where one of the components is considered to be
noncondensible (e.g., air), condensation occurs when the partial pressure of
the condensible component (e.g., VOC) becomes equal to the component's vapor
pressure. To achieve this condition, the system pressure may be increased at
a given temperature or the temperature of the vapors may be reduced at
constant pressure. ^ Figure 3-13 depicts a typical condensation system.
Condensation as an emission control method is often used with auxiliary
air pollution control equipment. For example, condensers can be located
before (upstream of) absorbers, incinerators, or C'irbon b
-------
TABLE 3-7. CHECKLIST FOR ABSORBERS
PLANT
LMtJ
i.
ii.
HACKliROUNI) INFORMATION
A. MANUFACTUKKR OF UNIT
U. INTALLATION DATE
C. RATED EFFICIENCY
INSPECTOR
DATE
IJ. TYPE OF ABSORBER: PACKED BED
OTHER (SPECIFY)
RATED CAPACITY (CFM)
SOLVENT UTILIZED
FILTER MESH V TRAY
E. COMPOSITION OF GAS STREAM ENTERING ABSORBER
F. TYPES AND NUMBER OF EMISSION POINTS VENTED TO ABSORBER
G. BED CONFIGURATION:
VOC Flilii) LINK
VERTICAL
HORIZONTAL \/"
A. IS IT STRUCTURALLY SOUND?
». 1. HOLES OR CORROSION OBSERVED?
YES
YES
NO
NO
2. II- YES, SKETCH FEED LINE AND HOLE UOCATLON BKLOW
(J. 1. FILTER INSTALLED ON FEED LINE? YES NO
2.
3.
4.
5.
1). FAN
I.
2.
TYPE OF FILTER
INSPECTION SCHEDULE
REPLACEMENT SCHEDULE
DATE OF LAST REPLACEMENT
FAN ON ABSORBER:
VIBRATION EVIDENT?
GLASS PAPER
PER
PER
INLET? v OUTLET?
YES NO V^
(continued)
79
-------
TABLE 3-7 (continued)
.-I. i i i i i • =
3. BUILD-UP ON FAN BLADES EVIDENT? YES * NO
4. CORROSION EVIDENT? YES NO *
5. EROSION EVIIM'iNT? YES NO
6. ARE THERE DAMPERS IN THE SYSTM? /i
-------
TABLE 3-7 (continued)
C. TYPE OF DEVICE (SPECIFY)
I). VOC OUTLET (JONCKNTKAWN DURING INSPECTION
V. ABSORBER COLUMN
0
A. COLUMN DIMENSIONS ~? FT x >> FT x O FT
II. EXTERIOR STRUCTURALLY SOUND? YES \S NO
C. 1. SOLVENT SPRAY NOZZLES INSPECTED / PER
2. SOLVENT SPRAY NOZZLES CLEANED _/_ PER
3. DATE OF LAST CLEANING
&CCusulfru
D. 1. TYPE OF PACK ING, ^ILTER) OR TRAY UTILIZED F\ICt £>*•
2. ABSORBER PACK TUG TRAY INSPECTED ' PER
3. ABSORBER PACKING TRAY CLEANED
4. DATE OF LAST CLEANING
&zZusdJ4M
E. 1. ABSORBER INTERNALS INSPECTED
2. ABSORIUW [Mlv.-'^ALS CLEANED /
3. DATE OF LAST CLEANING
F. PRESSURE DROP ACROSS COLUMNS
C. COMMENTS
(continued)
81
VI. SOLVENT RECIRCULATION LINE
A. STRAINERS AND/OR FILTER INSTALLED? YES \/ NO
B. INDICATE LOCATION OF FILTERS ON SKETCH BELOW
C. 1. STRAINERS/FILTERS INSPECTED / PER
2. STRAINERS/FILTERS CLEANED
3. DATE OK LAST CLEANING
-------
TABLE 3-7 (continued)
VII.
I). IS SOLVENT RECIROJLATION LINE BLED?
IF YES, FREQUENCY:
E. IS SOLVENT STRIPPED (DESORBED)?
IF YES, HOW?
SKETCH OF ABSORBER SYSTEM
YES
Oend&"U*<
-------
.VENT
INCOMING
VAf'OR
S
(
\
1
T
I
i
I
!
~|
A J
ir i
CONDLNSLR :-
^—
bi i
i m \
I I\-T ^
1 1 r
i *frf!-.
llu/-*
f"
COOLANT
RETURN
iJx,
f /-\/^| AKIT
SUPPLY
I
P
- -^L
VENT
v.,, .
fANK \
!-,
tf
d
REFRIGERATION
UNIT
RECOVERED VOC
TO STORAGE
-*
Figure 3-13. Basic surface condenser system.16
83
-------
When a condenser is used to control emissions, it is usually operated at
a conHfnut |> re.SHU re which is typically atmospheric. The two moot common types
of condensers that operate at atmospheric pressure are surface and contact
condensers. Most surface condensers are of the shell and tube type shown in
Figure 3-14. The coolant usually flows through the tubes, and the vapors
condense on the outside (shell) tube surface. The condensed vapor forms a
film on the cool tube and drains away to a collection tank for storage or
disposal. The coolant used depends on the temperature required for
condensation. Chilled water, brine, and refrigerants are normally used in
condensers. Air-cooled surface condensers are also available and are usually
constructed with extended surface fins. When the cool air passes over the
finned tubes, the vapors condense inside the tubes.l">2o
In contrast to surface condensers, where the coolant does not contact the
vapors or the condensate, contact condensers usually cool the vapor by
spraying an ambient-temperature or slightly chilled liquid directly into the
gas stream. The coolant is usually water, although in some situations a
material used in the process can be used as the coolant. These devices are
relatively uncomplicated, as is shown by the typical design in Figure 3-15.
Most contact condensers are simple spray chambers that are usually baffled to
ensure good contact. The coolant/VOC mixture exiting a contact condenser must
be separated if the coolant is to be reused.*"
Although contact condensers can be highly efficient in removing VOC from
a vapor stream, as in vacuum jet service, they can create additional
wastewater emission control problems downstream. Unless the VOC-contaminated
water discharged from the condenser is treated (e.g., stripped, absorbed,
extracted), secondary emissions will result from evaporation. Separation and
disposal requirements, along with the high cost of refrigeration, make
condensation an unattractive VOC control method.1°
As seen on Figures 3-13 through 3-15, condensers are relatively simple
devices, with an inlet vapor line, an atmospheric vent, a recovered VOC drain
line and coolant supply and return lines. Your inspection of this device will
therefore concentrate on insuring the physical integrity of these lines, and
verifying that the heat transfer surfaces (shell and tube design) or the spray
nozzles (contact design) are kept clean and free of scale or other deposits.
As discussed, you are more likely to encounter a condenser in conjunction with
an adsorber or an absorber than you are to find it alone.
Start your inspection with the VOC feed line. Is it structurally sound,
with no signs of leaks or corrosion? Do all metal to metal connections, such
as flanges, mate properly with no observable leakage of VOC? Does this line
have a filter on it for removing particulates and other contaminants? If so,
gather the relevant filter data.
Next check the atmospheric vent line. This line may have some form of
hydrocarbon analyzer on it to measure outlet VOC emissions. If it does,
record the type of device, and the current reading. Also check the plant
records for the readings of the previous 6 months, noting any wide fluxuations
that may indicate an O&M problem. If the vent line is near ground level, note
if there is an observable odor. Such an odor may be indicative of a poorly
84
-------
COOLANT
INLET
VAPOR
OUTLET
VAPOR
INLET
COOLANT CONDENSED
OUTLET VOC
Figure 3-14. Shell and tube surface condenser.16
VAPOR OUTLET
VAPOW INtf.T
Cf-NDENSATE
OLTLt. T
Figure 3-15. Contact condenser.16
85
-------
operating condenser, although you should not draw this conclusion without
checking back in your office the allowable emission rate and the odor
threshold for the VOC in use at the facility.
Now inspect the recovered VOC drain line. Is it structurally sound with
no signs of leakage or corrosion? Where does this line drain? How is this
drain tank emptied? Where does the VOC go from the drain tank? The flow of
condensed VOC from the condenser to the drain tank and on to final storage
should involve only a few lines and a liquid transfer pump. Take time to
follow this flow, and check each line and the pump for leakage.
Return to the condenser and inspect the coolant supply and return lines
and the refrigeration unit that is associated with them. For contact
condensers, this refrigeration system may be connected to the condensate
outlet line. As before, first insure that neither supply nor return lines
leak. Next verify the type of refrigerant used. Is it checked for impurities
on a regular basis? Is make-up refrigerant added regularly? How much is
added and how often? Has there been problems with some particular subunit,
such as the refrigerant compressor? Failure of the refrigeration unit will
cause uncontrolled VOC emissions, so it is important that you verify its
reliability.
Now turn your attention to the condenser itself. It will work as
designed as long as the VOC and coolant conditions are as specified and there
is no fouling of the internal surfaces that might affect heat transfer. To
the best extent possible, verify the composition, temperature and pressure of
the inlet VOC stream. Check and record the coolant supply temperature and
pressure. If these readings are kept by the plant on an operating log,
inspect ihese logs for noticeable changes over the past 6 months. Next
inspect the body of the condenser. Does it appear sound or are there signs of
leakage and corrosion? How often are the condenser internals inspected?
Cleaned? Has any repair work been done in the recent past?
Remember that very often the condenser will have little or no monitoring
and recording instrumentation. In this case you will have to investigate some
other secondary variable to ascertain how well the condenser is working. For
example, if the coolant is being fouled with organics, then this may indicate
a tube leak within the condenser. Or if the amount of VOC condensed is
monitored and recorded, you should check these records. A decrease in
condensed VOC that cannot be explained by process changes may indicate a
malfunction with the condenser that is resulting in the release of VOC into
the atmosphere. Finally, the condenser may be designed to capture one type of
VOC and that substance has since been replaced. Make sure you gather data on
VOC use so that you can check this against the type of VOC specified in the
facility's submittal to your agency. Table 3-8 is a checklist which provides
a complete list of items to be checked during a condenser inspection.
3.2.3 Ultimate Fate of Captured Emissions
The purpose of all the control devices discussed in Section 3.2.2 is to
remove the VOC from an exhaust stream and thereby prevent the release of the
VOC to the ambient air. With the exception of incinerators which destroy the
86
-------
TABLE 3-8. CHECKLIST FOR CONDENSERS
PLANT INSPECTOR
I. BACKGROUND INFORMATION DATE
A. 1. IS THE CONDENSER USED IN CONJUNCTION
WITH ANOTHER POLLUTION CONTROL
DEVICE? YES NO
2. IF YES, WHAT DEVICE
3. SKETCH SEQUENCE OF UNITS BELOW
B. TYPE OF CONDENSER: SURFACE CONTACT
OTHER (SPECIFY)
C. COOLANT/REFRIGERANT USED
II. VOC FEED LINE
A. IS LINE STRUCTURALLY SOUND? YES NO
B. ARE ALL CONNECTIONS TIGHT AND NONLEAKING? YES NO
C. L. DOES THIS LINE HAVE A FILTKR? YES NO
2. IF SO, WHAT TYPE: GLASS PAPER
OTHER (SPECIFY)
3. HOW OFTEN IS THE FILTER INSPECTED? PER
4. HOW OFTEN IS THE FILTKR CLEANED? PER
5. WHEN WAS IT LAST CLEANED?
III. VOC VENT
A. 1. IS A HYDROCARBON ANALYZER INSTALLED
ON THIS VENT? YES NO
2. IF SO, WHO IS THE MANUFACTURER AND WHAT IS MODEL NUMBER?
(continued)
87
-------
TAULG 3-8 (continued)
3. WHAT IS THE CURRENT READING?
4. IS THIS READING KEPT ON A LOG SHEET? YES NO
5. COMMENTS
B. 1. WHAT IS THE APPROXIMATE: HKT.GHT OF THE VENT LINE? FT
2. COULU YOU UliTECT AN ODOR FROM THIS
VENT? YES NO
3. COMMENTS
IV. VOC DRAIN LINE
A. IS THE LINK STRUCTURALLY SOUND? YES NO
B. 1. iM)!iS THIS LINE DRAIN INTO A RECOVERY
TANK? YES NO
2. SKI-ITCH THE POSITION OF THE CONDENSER
AND THK RECOVERY TANK BELOW
3. IS THE RECOVERY TANK ABOVE GROUND? YES NO
4. IF SO, IS IT STKUCTURALLY SOUND WITH
NO SIGNS OF CORROSION AND
DETERIORATION? YES NO
C. 1. WHERE IS THE RECOVERED VOC EVENTUALLY STORED?
2. SKETCH THIS TANK ON THE DIAGRAM BELOW
D. 1. IS A PUMP USED TO TRANSFER THE VOC
FROM THE CONDENSER TO THE RECOVERY
TANK? YES NO
2. FROM THE RECOVERY TANK TO STORAGE? YKS NO
3. DO EITHER OR BOTH OF THESE PUMPS SHOW
SIGNS OF LEAKAGE? YES NO
(continued)
88
-------
TABLE 3-8 (continued)
K. UiMMKNTS
V. REFRITERATION SYSTEM
A. DO BOTH COOLANT SUPPLY AND RETURN LINES
APPEAR STRUCTURALLY SOUND WITH NO
LKAKAGE OR CORROSION? YES NO
U. 1. TYPE OF REFRIGERANT USED
2. REFRIGERANT CHECKED FOR IMPURITIES PER
3. REFRIGERANT LEVEL CHECKED PER
l*. DATE OF LAST REFRIGERANT ADDITION
AND THE gUANTITY
C. 1. 4AS THE REFRIGERATION UNIT HAD ANY
PAST OPERATIONAL PROBLEMS? YES NO
2. IF SO WHAT WAS THE PROBLEM?
3. HOW LONG WAS THE UNIT OFF-LINE?
I). I. MIE SPARE PARTS KEPT FOR ANY PART
01' Tilt: REFRIGERATION SYSTEM? YES NO
2. IF SO, WHAT PARTS?
K. 1. IF A CONTACT CONDENSER IS USED, HOW ARE
THK VOC AND WATER SEPARATED?
2. WHERE IS THE WATER DISPOSED?
IV. CONDENSER
A. WIPKRTIES OF THE INLET VOC STREAM:
TEMPERATURE °F PRESSURE
FLOW RATE CFM COMPOSITION (% VOC)
(continued)
89
-------
TABLE 3-8 (continued)
B. WHAT ARE THE INLET COOLANT PROPERTIES
TEMPERATURE °F PRESSURE
C. 1. CAN YOU INSPECT THE PLANT LOGS FOR THE
PAST 6 MONTHS FOR OPERATING VALUES? YES NO
2. IF SO, WERE THERE ANY NOTICEABLE
DEVIATIONS? YES NO
3. COMMENTS
D. 1. IS THE EXTERNAL SHELL OF THE
CONDENSER STRUCTURALLY SOUND? YES NO
2. ARE THERE ANY NOTICEABLE LEAKS? YES NO
E. I. IS THE INTERNAL SURFACE OF THE
CONDENSER REGULARLY INSPECTED? YES NO
2. DATE OF LAST INSPECTION
3. IS IT REGULARLY CLEANED? YES NO
4. DATE OK LAST CLEANING
1. HAS THE CONDENSER HAD A MAJOR
OVERHAUL FOR ANY REASON? YES NO
2. IF SO, WHY?
3. WHEN WAS THIS WORK DONE?
VU. COMMENTS
(continued)
90
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TABLE 3-8 (continued)
i i • • .cmn ;a s
VI11. SKETCH OF SYSTEM
91
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WC, the devices remove the VUG vapor from the air stream without really
chemically altering them. Once removed from the air stream, the VOC must
still be disposed of in a manner that prevents their release to the ambient
air. It is therefore extremely important that you find out what the plant
does with the VUC that are removed from the control device.
As was touched upon in the discussion of the control devices, some plants
will recover and reuse the VUC, others will containerize it and send it to a
reclaimer, while some will simply dispose of it. It is the method of disposal
that you must be concerned with. Some of the VOC become hazardous waste when
disposed and must therefore meet stringent regulations. However, your main
concern should be that the VOC are not allowed to evaporate after their
removal from control devices at the surface coating facility.
Ask your plant escort about the VOC removal and handling procedures.
Inspect any containers that are holding waste VOC. Are they tight enough to
prevent leaks or losses by evaporation? Does the plant leave them open until
they are full or close them after each use? If they are shipped off-site,
obtain the name of the reclaimer or transporter. Some facilities are allowed
to put their waste in the sewer system provided that it does not exceed
certain concentration limits.
3.3 PROCESS INSPECTION
The procedures for inspecting the emission control system will provide
you with an assessment of that system's operation and maintenance relative to
it's originally permitted conditions. However, even if the operation and
maintenance of the emission control system are found to be satisfactory, it is
possible that the emisson rat<* from the control system is different from the
rate permitted. Changes in emission rates can result from changes in the
surface coating process operation. Changes in process operation that can
effect the emission rate are:
• changes in coating compositions,
• changes in coating application methods,
• changes in coating application rate;.,
• changes in coating drying/curing methods or rates,
• changes in the material being coated.
Because of the variety and complexity of surface coating processes, a
detailed description of inspection methods that would provide a basis for
quantifying emission rate changes that would result from process changes is
beyond the scope of this document. However, while you are conducting your
inspection of the surface coating process emission control system, you should
gather some information on the current surface coating operation.
92
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Start your inspection of Che surface coal ing process at the point where
the coating is applied to the material being coated (i.e., the applicator).
Ask your company escort about the composition of the coating and the
application method being used. Find out if they change the types of coatings
applied by the applicator. How often are they changed? What are the
differences between coatings? Do they buy the coatings from different
uupplicrs?
Tin: compositions of the different coatings are important. The more
solvent in a coating the more will enter the control system. Different
suppliers may use different solvents that have different evaporation rates.
Thus, the amount of solvent evaporated from the applicator versus the curing
ovon could change and this may require rebalancing of the capture system.
Different solvents also exhibit different adsorption, condensation, and
absorption characteristics. A control device originally designed for a
certain type and amount of solvent may exhibit a different effectiveness of
VOC removal if the type of solvent is changed. This is not a problem if the
efficiency increases, but an efficiency decrease may result in emissions in
excess of permitted conditions. Sometimes it requires only adjustment to a
control device operating parameter (temperature, regeneration cycle) to regain
effective operation. Ask plant personnel if they change any part of the
control system when they change coatings.
Next, observe the material being coated and the coating application
method. Make a note of both the coating application method (spray, flow, dip,
etc.) and the shape of the material being coated (chairs, fenders, discs,
springs, etc.). Ask plant personnel if they have made any changes to the
application method recently. Have they changed the rate at which they apply
the coating? Can they coat other shapes on the same line? Do they change
shapes often? Do they change the application rate for different shapes? What
adjustments do they make to the applicator when they change shapes? Do they
ailjust the control system when they make adjustments to the applicator?
Next observe the drying/curing area of the line. Make a note of the way
the coating is dryed/cured onto the material (gas-fired oven, infrared
heaters, stacked in room). Many ovens operate continuously with material
movciil through them on some type of conveyor system. Can the conveyor speed be
changed? What circumstances cause it to be changed? Is the temperature of
the drying/curing operation monitored? Is it necessary to vary the
temperature frequently? Check the physical integrity of the ovens you may
see. When ovens are totally enclosed, the capture system will often evacuate
them directly. Thus, they should be under negative pressure and fumes should
not be observed leaking from the entrance or exit of the ovens. However, a
crack or space between oven panels may allow Loo much air into the oven and
overload the capture system. The drying/curing process is important to the
quality of the coating and, therefore, the drying/curing equipment is likely
to be well maintained.
Because of the diversity of coating process equipment a suggested
checklist is not presented, since one that would cover all possibilities would
be too cumbersome and a general one would be of little practical value.
93
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liiMl.iM'l, ( lie pr^ct'd iny, discussion is intended to inform you of the changes to
Hie :uirliu:e coating process that can be made mid the fact that these changes
can in! lunnce the control system's ability to perform as originally designed.
Plant personnel may, in some cases, be genuinely unaware of the influence that
process changes can have on the control system. By asking about process
changes you will be able to identify potential changes in emission rates when
the information you collect is compared to the original permit conditions.
3.4 PLANT INSPECTION
This document is not intended to provide you with detailed procedures for
inspecting all operations at a surface coating facility. However, if your
time schedule allows, you should make a brief "walkthrough" inspection of all
operating ;ind storage areas of the plant.
Investigate any noise, odor, or fugitive emission problems you may have
not^.d when you conducted your preinspection circumnavigation of the facility.
Note the raw material and finished product storage areas. Make a note of
noise producing processes or operations, their proximity to the facility
property line, and the potential for the noise to reach the nearest off-site
receptor. Note operations that are odorous or dust producing and also attempt
to evaluate the potential for odors or dust from these sources to leave the
plant property.
IE the plant operates a boiler you should inspect it for obvious signs of
improper operation or malfunction. Another guidance document is available
that will provide you with detailed inspection procedures. However, obvious
signs of boiler problems are a smoky stack or erratic boiler temperature.
Finally, if during your preinspection file review you noticed a recurring
emission problem or citizen complaint, you should inspect that equipment.
Make sun; that the plant is still taking steps to eliminate recurrance of the
past problems.
94
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4.0 REFERENCES
1. Control of VOC Emissions from Existing Stationary Sources, Volume 5:
Surface Coating of Large Appliances, OAQPS Guidelines.
liPA-4'iO/2-77-034. U.S. Environmental Protection Agency, Research
Triangle Park, NC. December 1977.
2. Automobile and Light-Duty Truck Surface Coating Operations—Background
Information for Proposed Standards. EPA-450/3-79-030. U.S.
Environmental Protection Agency. Research Triangle Park, NC. September
1979.
3. Control of VOC Emissions from Existing Stationary Sources, Volume 8:
Graphic Arts-Rotogravure and Flexography, OAQPS Guidelines.
EPA-450/2-78-003. U.S. Environmental Protection Agency. Research
TrianjjlR Park, NC. December 1978.
4. Control ot VOC Emissions from Existing Stationary Sources, Volume 7:
Factory Coating of Flat. Wood Paneling, OAQPS Guidelines.
liPA-450/2-78-032. U.S. Environmental Protection Agency. Research
Triangle Park, NC. June 1978.
r>. IJufkin, ll. G'. and G. C. Wildman. Materials Finishing. Presented at the
Workshop on Hydrocarbon Control from Selected Processes. Atlanta, GA.
June 27, 1977.
o. Pressure Sensitive Tape and Label Surface Coating Industry—Background
Information for Proposed Standards. EPA-450/3-80-003a. U.S.
Knvironmental Protection Agency. Research Triangle Park, NC. September
1980.
7. Kirk-Othmer Encyclopedia of Chemical Technology, 3rd Edition. John Wiley
and Sons. New York, NY. 1978.
8. Control of VOC Emissions from Existing Stationary Sources, Volume 4:
Surface Coating for Insulation of Magnet Wire, OAQPS Guidelines.
KPA-450/2-77-033. U.S. Environmental Protection Agency. Research
Triangle Park, NC. December 1977.
9. (leverage Can Surface Coating Operations—Background Information for
Proposed Standards. EPA-450/3-80-036a. U.S. Environmental Protection
Agency. Research Triangle Park, NC. December 1980.
95
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1.0. Surface Coating of Metal Furniture—Background Information for Proposed
Srandards. li!PA-450/3-80-007a. U.S. Environmental Protection Agency.
Nest:arch Triangle 1'ark, NC. September 1980.
11. Control of VOC Emissions from Existing Stationary Sources, Volume 6:
Surface Coating of Miscellaneous Metal Parts and Products, OAQPS
Guidelines. EPA-450/2-78-015. U.S. Environmental Protection Agency.
Kesearch Triangle Park, NC. June 1978.
12. AC(iJ.II Committee on Industrial Ventilation. Industrial Ventilation. A
manual of recommended practice, 14th Edition Lansing, Michigan: American
Convorence of Governmental Industrial Hygienists, 1976.
13. McDennott, H. J., Handbook of Ventilation for Contaminant Control. Ann
Arbor Science. Ann Arbor, Michigan. 1979.
14. Kent, K. W. A Guide to Catalytic Oxidation Oxy-Catalyst, Inc.. Research
<* Cotrell, Inc. West Chester, PA (In-house brochure).
15. Organic Chemical Manufacturing, Volume 4: Combustion Control Devices,
KPA-450/3-80-026, U.S. Environmental Protection Agency, Research Triangle
I'ark, North Carolina, December 1981.
16. Organic Chemical Manufacturing Volume 5: Adsorption, Condensation and
Adsorption Devices. EPA-450/3-80-027. U.S. Environmental Protection
Agency. Research Triangle Park, NC. December 1980.
17. I'armole, C. S., et al. Vapor-Phase Cuts. Chemical Engineering. 86(28):
58-70. December 1979.
16. Handbook tor the Operation ;md Maintenance of Air Pollution Control
Equipment. H. E. Heskoth and F. L. Cross, Editors. Technomic Publishing
Co. Westport, CT. 19/5.
19. Air 1'ollution Engineering Manual AP-40, 2nd Edition. J. A. Danielson,
Editor. U.S. Environmental Protection Agency. Research Triangle Park,
NC. May 1973.
20. Air I'uritication with (Iranular Activated Carbon. Manufacturers
Brochure. Calgon Corporation. 1975.
21. Cheremisinoff, N. P. Process Level Instrumentation and Control. Marcel
Dekker, Inc. New York, NY. 1981.
22. Monitoring Carbon Bed Breakthrough. Manufacturers Brochure. Foxboro
Company. 1980.
21. Personnel Communication between Charles Tozzo, Gravure Research Institute
and Brian llobbs, GCA. January 28, 1982.
96
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24. McCabe, W. I,, and J. C. Smith. Unit Operations of Chemical Engineering,
3rd Edition. McGraw-Hill Co., New York, NY. 1976.
2'>. I'l.'ttrH, M. S. ami K. I). TiinnwrhauB, Plant Design and Economics tor
Chemicnl Engineers. 2nd ed.
2(>. Treybal, K. E. Mass Transfer Operations. 2d ed. McGraw-Hill. New
York. 1966.
27. Personal communication between Dan Nagel, Ametek Schutte & Koerting and
Brian Hobbs, GCA. January 19, 1982.
2rf. Varg.-is, K. J. Troubleshooting Compression Refrigeration Systems.
Chemical Engineering, 89(6): 137-143. March 1982.
97
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5.0 ANNOTATED BIBLIOGRAPHY
In this annotated bibliography, the codes in the columns to the right of
each entry indicate the topical arei'S discussed by the document. The
abbreviations used have the meanings described below.
SCI* = Surface Coating Process; the document includes information on one
or more types of surface coating operations, including coating types.
CS = Capture System; hoods, ductwork, fans.
ACI-; = Adil-on Control Equipment; description of control equipment design
aiul/or operation and maintenance.
I = Incinerator
A = Adsorber
Ab= Absorber
II = Hoods
D = Ductwork
L1' = lr.ins
X - Some general information on more than one of the above items
(t) = Text is more theoretical than practical
SCP CS ACE
Chemical l-lnginorirs Handbook, 5th ed. Perry and Chilton. A
Mi-.Uraw-lli U, New York (1973). In depth technical Ab
information on the theory and design of absorption and
adsorption systems. Areas of discussion include mass
transfer, solubility, system components and unit design
equations and calculations.
Unit Operations of Chemical Engineering, 3rd Ed. McCabe and Ab
Smith. McGraw- Hill, New York (1976). Analyses of gas
absorption systems with an emphasis on unit: design. The
information covered includes determination of mass transfer
r/ites, gas-liquid ratios, pressure drops and temperature
variations. Also, types of tower packing ire evaluated
for effectiveness.
98
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SCP CS ACE
Kirk-Othmer K.ncyc lopedia of Chemical Technology, 3rd Ed. John I
Wiley ^ Sons, New York (1978).Sizeable amount of A
infonnation devoted to the general theory and application Ab
design methods for absorption, incineration and adsorption
systems. Topics include solubility, mass transfer,
diffusion, types of columns, regeneration, industrial
applications, multicomponent separations, furnaces, catalytic
incineration and fluidized beds.
Bibliography of Solid Adsorbents, 1942-1953. Deitz, V. R. A
Washington, D.C. Detailed classification of adsorbents
used in gas-solid separation systems.
On Physical Adsorption. Ross and Olivier. Interscience A(t)
Publishers, New York (1964). Intensely quantitative book
on the authors' development of adsorption theory based on
experimental data. Areas covered include molecular
properties, structure of surfaces and calculation of
isotherms.
Physical Adsorption of Gases. Young and Crowell. Butterworths, A(t)
London (1962). A compilation of theoretical adsorption
analyses. Much of the theory is based on experimental
results and pertains to; surface phenomena, measurement of
isotherms, thermodynamics and calculation of adsorption
parameters.
The Mcllvaine Scrubber Manual. This manual contains extensive X Ab
infonnation on absorber systems. Areas covered include;
basic scrubber types, major system problems, vendor
descriptions of units and design and maintenance information.
I'Lani Design and Economics for Chemical Engineers, 3rd Ed. Peters XXI
and Timmerhaus. McGraw-Hill, New York (1980). This A
publication deals mostly with the economic aspects of Ab
industrial operations and plant design. It also contains
updates on plant technologies including absorption units.
Mass-Transfer Operations, 3rd Ed. Treybal. Technical informa- Ab
tion on the principles behind masp-transfer operations.
Packed towers and staged columns are covered along with new
types ot tray towers and headless absorbers.
Handbook for the Operation and Maintenance of Air Pollution X I
Control Equipment. Hesketh and Cross. Technomic, Westport, A
Connecticut (1975). This handbook contains a chapter on Ab
each of the following control devices; incinerators,
adsorbers and absorbers. Included in each chapter are
sections on equipment, operation, maintenance and factors
that affect performance.
99
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SCP CS ACE
Air PolLution Aspects of Emission Sources: Surface Coatings— X XX
Th(?ir Production and Use—A Hibliography wiih Abstracts.
!• PA-450/1-74-005. U.S. EPA. Office of Air Quality Planning
and Standards. Research Triangle Park, NC 27711. March
1974. A compilation of approximately 235 abstracts of
documents addressing the following surface coating subject
categories: emission sources; control methods; measurement
methods; basic science and technology; and others. Abstracts
cover professional journals and government reports, foreign
and domestic.
Afterburner Systems Study. EPA-R2-72-062. Rolke, R. W., HI
K. U. Hawthorne, C. R. Garbett, et al. Shell Development 1)
Company for U.S. EPA, Office of Air Programs, Research F
Triangle Park, NC 27711. August 1972. This 512-page
document covers the design, operation, and costing of all
the different types of afterburner or fume incinerator
systems that can be employed to control gaseous combustible
emissions from stationary sources. Information is presented
in handbook format and includes numerous drawings, pictures,
tables, and graphs. The incinerator and all major subsystems
are discussed and potential problems and recommended design
features are presented.
Wet Scrubber System Study, Volumes I and II. EPA-R2-72-118a & b. X Ab
Culvert, U., J. G. Goldshmid, D. Leith, D. Mehta. APT, Inc.
for U.S. KPA, Office of Air Programs, Control Systems
Division, Research Triangle Park, NC 27711. August 1972.
Tliis M25-pa^'i, two-volume document covers i~he design and
operation of all types of wet scrubbers us>:d to reduce solid
or gaseous contaminant concentrations in gas streams.
Auxiliary systems, costing procedures, design examples, and
troubleshooting are described and discusser. Numerous figures
and tables are included. The bibliography presented in
Volume IE contains about 1,700 references discussing various
aspects of wet scrubbers.
Package Sorption Device System Study. EPA-R2-7J-202. U.S. EPA, XXI
Office of Research and Monitoring, Research Triangle Park, A
NC 27711. April 1973. This 516-page document covers all
.•ispects ot adsorption of organic materials. The conditions
ot release of pollutants from more than 17 industrial
sources, including surface coating, are presented. Sorbent
types and adsorption theory are presented in detail.
Incineration systems are presented. Auxiliary systems for
both types of controls are compared. Examples of calculation
procedures are included in appendices. References and a
bibliography are included.
100
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/ SCP CS ACE
Air Pollution Control Technology and Costs in Seven Selected
Areas. EPA-450/3-73-010. By IGCI for U.S. EPA, Research
Triangle Park, NC 27711. December 1973. This document
contains ;i detailed description and data related to the
Graphic Arts industry. Process types, solvents used,
<:haracterization of emission streams and control equipment
types and costs are subject areas discussed in detail.
Numerous flow sheets, tables, graphs, and roferances
supplied.
Systems and Costs to Control Hydrocarbon Emissions from
Stationary Sources. EPA-450/2-74-006. U.S. EPA, Office
of Air Quality Planning and Standards, Research Triangle
Park, NC 27711. September 1974. Brief overview of surface
coating and graphic arts processes, control equipment, and
costs. Some references provided.
Air Pollution Control Technology and Costs Seven Selected
Emission Sources. liPA-450/3-74-060. By IGCI for U.S. EPA,
Office of Air Quality Planning and Standards, Research
Triangle Park, NC 27711. December 1974. General presenta-
tion of surface coating application methods, emission?.,
controls, and costs. Charts, flow sheets, graphs, and
tables inc Luded.
IU;port of Fuel Requirements, Capital Cost and Operating Expense
for Catalytic and Thermal Afterburners. EPA-450/3-76-031.
U.S. EPA, Office of Air Quality Planning and Standards,
Kesearch Triangle Park, NC 27711. September 1976.
Presents limited design and operating characteristics of
incineration equipment to control different inlet concentra-
tions of volatile organic compounds. Aimed primarily at
cost comparison.
Livaluniion of a Carbon Adsorption/Incineration Control System for
Auto Assi.-mbly Plants. EPA-909/9-76-002. U.S. EPA, Region
LX, 100 California St., San Francisco, CA 94111. May 1976.
Detailed description of paint application and baking oven
processes at auto assembly plants. Description of emissions
from these operations and control equipment which can be
used to reduce emissions. Process and control economics and
energy considerations are presented.
Control Techniques for Volatile Organic Emissions from
Stationary Sources. EPA-450/2-78-022. U.S. EPA, Office of
Air (Duality Planning and Standards, Research Triangle Park,
NC 27711. May 1978. This document is intended primarily
as a general reference for State and local air pollution
control engineers. It includes: basic information on
101
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SCP CS ACE
sources of VUG and control of these sources; estimates of
control costs; estimates of energy requirements, and;
estimates of achievable emission reductions. All the major
surface coating categories are discussed. References are
included.
I/
Management and Technical Procedures for Operation and Maintenance H Ab
of Air Pollution Control Equipment. EPA-905/2-79-002. U.S. D
EPA, Region V, 230 S. Dearborn, Chicago, IL 60604. June F
1979. Focus on particulate controls. However, information
provided on scrubbers is universally applicable. Guidance on
fans, ductwork, etc. that is applicable regardless of control
device or pollutant controlled. Includes a bibliography.
Enforceability Aspects of RACT for Factory Surface Coating of X
Flat Wood Paneling.EPA-340/1-80-005.U.S. EPA, Division
of Stationary Source Enforcement, Washington, DC 20460.
April 1980. General description of the industry and control
methods. References are supplied and an Appendix contains a
detailed list of 57 flat wood paneling coaters.
Preliminary Environmental Assessment of Afterburner Combus~ X XI
tion Systems. EPA-600/7-80-153. U.S. EPA, Office of
Research and Development, Research Triangle Park, NC 27711.
June 1980. Provides a general assessment of afterburner
effectiveness in reducing organic emissions. Numerous source
types are addressed. A summary and review of applicable
regulations is provided.
Assessment of Organic Emissions in the Flexible Packaging X H X
Industry. EPA-600/2-81-009. U.S. EPA, Office of Research F
and Development, Cincinnati, OH 45268. January 1981. D
Contains detailed descriptions of process operations and VOC
control alternatives in the flexible packaging industry.
Economics are also presented in detail. Study conducted by
cont.-ict ing actual facilities through assistance from the
Flexible Packaging Association.
Catalytic Incineration of Low Concentration Organic Vapors. X I
EPA-600/2-81-017. U.S. EPA, Office of Research and
Development, Research Triangle Park, NC 27711. February
1981. Detailed description of the operation and effective-
ness of a pilot-plant catalytic incinerator on the exhaust
from a plastic printing operation. Discussion of the effects
of varied operation parameters on unit ef1iciency.
102
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SCP CS ACE
Determination of Capture and Destruction Efficiencies of Selected X I
Volatile Organic Compound Control Devices in the State of A
Illinois. EPA-905/2-80-005. U.S. EPA, Region V, 230 S.
Dearborn, Chicago, 1L 60604. December 1980. Describes the
results of tests conducted at paper and can coaters in
Illinois. Both afterburners and adsorbers were tested.
Information is presented on possible means of improving the
performance of the control systems. Descriptions of processes
and control equipment are provided.
Summary of Technical Information for Selected Volatile Organic XXX
Compound Source Categories. EPA-400/3-81-007. U.S. EPA,
Office of Air Quality Planning and Standards, Research
Triangle Park, NC 27711. May 1981. Compilation of existing
information of varying detail based on review of the technical
literature, published and unpublished EPA, State and local
agency reports. Eighteen stationary source types are
discussed including: fabric printing; plastic parts painting;
and wood furniture coating. Process, emission, control
technology, regulatory status, and references are topics
covered for each industry category.
Organic Emissions Evaluation of a Paint Bake Oven with Catalytic XXI
Incineration. EPA-600/2-81-244. U.S. EPA, Office of
Research and Development, Cincinnati, OH 45268. October
1981. Presents test results of catalytic incinerator with
heat recovery on oven at a truck painting plant. Descrip-
tion of process and control equipment included. Inlet and
outlet to incinerator were tested.
Control of VCK- Emissions from Existing Stationary Sources, X X
Volume I: Control Methods for Surface Coating Operations,
OAQPS Guidelines.EPA-450/2-76-028.U.S. EPA, Office of
Air Quality Planning and Standards, Research Triangle Park,
NC 27711. November 1976. Available methods which can be
used to control emission of organic vapors from surface
coating operations are described. The methods consist of
two types: (1) add-on control equipment, and (2) process
and material changes. Add-on equipment described includes
thermal and catalytic incinerators, and activated carbon
adsorbers. Graphs are presented that allow costing of these
units for varying process stream conditions and control
equipment design. Numerous references are provided.
Incinerator Problems and How to Prevent Them. Heady, D. F. and X I
R. F. Schwab. Chemical Engineering Progress. 76(10):52-57.
October 1980. Provides a discussion of five ca >es of
incinerator failure. Focuses on an actual incinerator burning
phthalic anhydride and a multipurpose incinerator, both at
an Allied Chemical Corp. plant.
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APPENDIX A
ABBREVIATIONS
acfm: Actual cubic feet per minute
15ID: Background Information Document
Htu: British thermal unit.
(JIG: Control Technique Guideline
fpm: Feet per minute.
LEL: Lower Explosive Limit
NSPS: New Source Performance Standard
psia: Pounds per square inch absolute
psig: Pounds per square inch guage
psi: Pounds per square inch
11ACT: Reasonably Available Control Technology
VUC: Volatile Organic Compounds
104
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APPENDIX B
GLOSSARY
absorption: The transfer of one or more constituents from a gaseous mixture
to a liquid, in which the absorbed material may dissolve physically or
react chemically. (Packed, plate, and spray towers are typical
absorption devices.)
absorbatc: Substance being adsorbed; typically organic vapors.
aclivated carbon: Highly porous, nonpolar adsorbent produced from bituminous
coal.
actual cubic feet per minute: The volume flow per minute of gas at actual
conditions of temperature, pressure and composition.
adsorbent: Solid material used to collect vapors and liquid by molecular
interaction.
adsorption: Removal of impurities from a gas stream by concentration of the
impurities on the surface of a solid or liquid. (Commercial adsorbents
have a large surface area per unit weight.)
.•lerosoL: An assemblage of small particles, solid or liquid, suspended in air.
Thf diameter of tlie particles may vary from 100 microns down to 0.01
micron or IP.SS, e.g., dust, fog, smoke.
afterburner: A final burner stage that removes undesirable volatile matter
through incineration.
nir cleaner: A device designed for the purpose of removing atmospheric
airborne impurities such as dusts, gases, vapors, fumes and smokes. (Air
cleaners include air washers, air filters, electrostatic precipitators
and charcoal filters.)
air filter: An air cleaning device to remove light particulate loadings from
normal atmospheric air before introduction into the building. Usual
ran^.e: loadings up to 3 grains per thousand cubic feet (0.003 grains per
cubic foot). Note: Atmospheric air in heavy industrial areas and
in-plant air in many industries have higher loadings than this and dust
collectors are then indicated for proper air cleaning.
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BjirkK round tnfonnation Document: (also denoted as BID) A technical document,
developed by the Environmental Protection Agency, pertinent to an
emission source category, which examines the technical and economic
impacts of imposing a New Source Performance Standard on the subject
emission source category.
balancing by dampers: Method for designing local exhaust system ducts using
adjustable dampers to distribute airflow after installation.
balancing by static pressure: Method for designing local exhaust system ducts
by selecting the duct diameters that generate the static pressure to
distribute airflow without dampers.
bed: Vessel containing supported inert solid shapes for adsorption or
absorption.
bed fire: Combustion occurring in adsorption beds caused by excessive heat
buildup and organic concentrations above the lower explosive limit.
brake horsepower: The horsepower actually required to drive a fan. This
includes the energy losses in the fan and can be determined only by
actual test of the fan. (This does not include the drive losses between
motor and fan.)
breakthrough: Point at which concentration of organic vapors in gas stream
exiting adsorption bed exceeds a preset emission limit.
capture system: The equipment (including hoods, ducts, fans, etc.) used to
capture;, contain, or transport a pollutant to a control device.
capture velocity: The air velocity at any point in front of the hood or at
th«? houd opening necessary to overcome opposing air currents and to
capture the contaminated air at that point by causing it to flow into the
hood.
coating line: One or more apparatus ot operations which include a coating
applicator, flash-off area, and oven wherein a surface coating is
applied, dried, and/or cured.
contaminant: Anything added to the environment that causes a deviation from
the mean geochemical composition. (Same as pollutant.)
controls: Measurement and instrumentation devices used to monitor and adjust
process conditions.
Control Technique Guideline: (also denoted as CTG) A technical document,
developed by the Environmental Protection Agency, pertinent to an
emission source category, which examines the technical and economic
feasibility of imposing various emission control equipment or emission
limit requirements on existing sources.
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convection: The motion resulting in a fluid from the differences in density
and the action of gravity. In heat transmission this meaning has been
extended to include both forced and natural motion or circulation.
cycle time: Amount of time it takes for an adsorption system to adsorb,
regenerate, cool and dry.
dumpers: Adjustable sources of airflow resistance used to distribute airflow
in a ventilation system.
decant: (Gravity separation of immiscible liquids (e.g., water and organica.)
desorb: (See Regenerate.)
differential pressure: The difference in static pressure between two
locations.
duct: A conduit used for conveying air at low pressures.
dust: Small solid particles formed by the breaking up of larger particles.
effluent: A discharge or emission of a fluid.
emission: The discharge or release, whether directly or indirectly, of air
pollutants into the ambient air from any source.
entrainment: Bulk diffusive carryover of solid or liquid particles in a
gaseous stream.
fan static pressure: The pressure added to t!ie system by the fan. It equals
the sum of pressure losses in the system minus the velocity pressure in
the air at the fan inlet.
flange: A rim or edge added to a hood to reduce the quantity of air entering
the hood from behind the hood.
flue gas: Gaseous emissions discharged through a flue or stack.
formulation: Coating mixture containing various ingredients blended to meet
particular specifications.
friction loss: The pressure loss due to friction.
fumes: Small solid particles formed by the condensation of vapors of solid
materials.
gases: Formless fluids which tend to occupy an entire space uniformly at
ordinary temperatures and pressures.
lied: Amount of residual organic material left in adsorption bed after
regeneration, cooling and drying.
107
-------
liood: A shaped inlet designed to capture contaminated air and conduct it into
the exhaust dust system.
hood, canopy: A hood that is located over a source of emissions.
hood, capturing: A hood with sufficient airflow to reach outside of the hood
to draw in contaminants.
hood, enclosing: A hood that encloses the contaminant source.
hood, lateral: See hood, capturing.
hood, receiving: A hood sized and located to catch a stream of contaminants
or contaminated air directed at the hood.
hood, slot: A hood consisting of a narrow slot leading into a plenum chamber
under suction used to distribute air velocity along the length of the
slot.
hood entry loss: The pressure from turbulence and friction as air enters the
ventilation system.
hood static pressure: The suction of static pressure in a duct near a hood.
It represents the suction that is available to draw air into the hood.
hot spot: Area in an adsorption bed where inadequate ventilation has led to
heat buildup.
humidity, relative: The ratio of the actual partial pressure of the water
vapor in a space to the saturation pressure of pure water at the same
temperature.
inch of water: A unit of pressure equal to the pressure exerted by a column
of liquid water 1 in. high at a standard temperature.
incineration: Combustion of solid, liquid or gaseous wastes under controlled
conditions.
inclined manometer: A manometer that amplifies the vertical movement of a
water column through the use of an inclined leg.
inert gas: Common purge material.
lower explosive limit (LEL): The lower limit of flammability or explosibility
of a gas or vapor at ordinary ambient temperatures expressed as percent
of gas or vapor in the air by volume.
manometer: An instrument for measuring pressure; essentially a U-tube
partially filled with a liquid, usually water, mercury or a light oil, so
constructed that the amount of displacement of the liquid indicates the
pressure being exerted on the instrument.
108
-------
minimum design duct velocity: Minimum air velocity required to move the
particulates in the air stream.
mists: SmalL droplets of materials that are ordinarily liquid at normal
temperature and pressure.
New Source Performance Standards: (also denoted as NSPS) An emission control
equipment requirement or an emission limit promulgated by the
Environmental Protection Agency and applicable to all new sources in an
identified emission source category unless a more stringent state
standard applies.
organics: Chemical substances containing carbon atoms. Beside water, most
substances used in coating applications are organic.
oxidants and ozone: In air pollution technology, ozone and oxidants are the
result of photochemical reactions between nitrogen oxides and some
organic pollutants. The concentrations of ozone and oxidants in the
atmosphere are an index of photochemical smog.
particulate: Airborne material that has a relatively fixed shape and volume
such as dusts, mists, smokes and fumes.
personal protective equipment: Devices worn by persons to protect against
hazards in the environment. Respirators, gloves and ear protectors are
examples.
pi tot; tube: A device for measuring pressure consisting of two concentric tubes
arranged to measure total and static pressure.
pressure, atmospheric: The pressure due to the weight of the atmosphere. It
is the pressure indicated by a barometer. Standard Atmospheric Pressure
or Standard Atmosphere is the pressure of 29.92 inches of mercury.
pressure, static: The potential pressure exerted in all directions by a fluid
at rest. For a fluid in motion it is measured in a direction normal to
the direction of flow. Usually expressed in inches water gauge when
dealing with air. (A measure of the tendency to either burst or collapse
a container.)
pressure, total: The algebraic sum of the velocity pressure and the static
pressure (with due regard to sign).
pressure, vapor: The pressure exerted by a vapor. If a vapor is kept in
confinement over its liquid so that the vapor can accumulate above the
liquid, the temperature being held constant, the vapor pressure
approaches a fixed limit called the maximum or saturated, vapor pressure,
dependent only on the temperature and the liquid. The term vapor
pressure is sometimes used as synonymous with saturated vapor pressure.
109
-------
pressure, velocity: The kinetic pressure in the direction of flow necessary
to ciiuse a fluid at rest to flow at a given velocity. Usually expressed
in inches water gauge.
pressure drop: The difference in static pressure measured at two locations in
a ventilation system due to friction or turbulence.
pressure loss: Energy lost from a ventilation system through friction or
turbulence.
psi: Pounds per square inch. A measure of pressure. 1 psi equals 27.7 inch
water gauge; or 2.04 inch Hg.
psia: Pounds per square inch aboslute. The absolute pressure without
reference to another point. Standard atmospheric pressure is 14.7 psia.
psig: Pounds per square inch gauge. The pressure relative to atmospheric
(0 psig equals 14.7 psia).
purge: Removal of residual material by the passing of fluid (typically gas)
through a system.
push-pull hood: A hood consisting of an air supply system on one side of the
contaminant source blowing across the source and into an exhaust hood on
the other side.
Reasonably Available Control Technology: (also denoted as RACT) The lowest
emission limit that a particular source is capable of meeting by the
application of control technology that i.c reasonably available
considering technological and economic feasibility. It may require
technology that has been applied to similar, but not necessarily
identical, source categories.
regenerate: Removal of adsorbate from adsorbent, lypically by raising
temperature or lowering pressure.
scrubber, gas: Any device in which a contaminant, solid or gaseous, is removed
from a gas stream by liquid droplets. (Types include spray towers,
packed towers, cyclone scrubbers, jet scrubbers, venturi scrubbers,
impingement scrubbers and mechanical scrubbers.)
solute: Soluble component of a vapor stream which is absorbed by a
solvent.
solvent: As used in reference to surface coatings, organic materials which are
liquid at standard conditions and which are used as dissolvers, viscosity
reducers, or cleaning agents.
spent: As used in reference to an adsorbent or absorbent, saturated.
standard air density: The density of air, 0.075 Ib/ft-*, at standard
conditions.
110
-------
standard conditions: In industrial ventilation; a temperature of 70°F, 50
percent relative humidity and 29.92 inches of mercury atmospheric
pressure.
tnchometer: A device for measuring rotating speed.
transport (conveying) velocity: See Minimum Design Duct Velocity.
turbulence loss: The pressure or energy lost from a ventilation system
through air turbulence.
turning vanes: Curved pieces added to elbows or fan inlet boxes to direct air
and so reduce turbulence losses.
velocity, face: The inward air velocity in the plane of openings into an
enclosure.
velometer: A device for measuring air velocity.
ventilation, local exhaust: A system, usually consisting of hoods, ducts, air
cleaner and fan, that captures or contains contaminants at their source
for removal from the work environment.
ventilation, mechanical: Air movement caused by a fan or other air moving
device.
ventilation, natural: Air movement caused by wind, temperature difference or
other nonmechanical factors.
valve: An adjustable orifice used to control fluid flow.
vapor: The gaseous form of substances which are normally in the solid or
liquid state and which can be changed to these states either by
increasing the pressure or decreasing the temperature.
Volatile Organic Compound: (also denoted as VOC) Any organic compound which
participates in atmospheric photochemical reaction or is measured by the
applicable reference methods specified under my subpart of 40 CFR 60.
Ill
-------
APPENDIX C
INSPECTION CHECKLISTS
This appendix contains blank copies of the inspection checklists that
were presented as Tables 3-2 through 3-8 in Section 3.0 of this report. They
are presented here in a reduced format, but are otherwise identical to those
in the text. They are printed on only one side of the page. Thus, they can
bfi readily copies to provide a 'checklist that is useable in the field and
contains a minimum number pages. It is suggested that the backs of each page
can be used for additional notes and sketches.
112
-------
TABLE C-l. CHECKLIST FOR HOODS
PLANT
UAH;
I.
PROCESS
A. PR--JESS LIKi RESIGNATION
B. HOCESS EQUIPMENT CDNTKOLLED BY iOOD
C.
D.
PROCESS IN OPERATION DURING INSPECTION? YES NO
1. PROCESS OPt:1ATINC AT MAXIMUM CAPACITY? YES NO
2. IF NOT, AT APPROXIMATELY WHAT PERCENT C'F CAPACITY?
ii. moo
A. TYPE OF HOOD: ENCLOSURE RECEIVING
CAPTURE OTHER (DESCRIBE)
IS THE HOOD STRUCTURALLY SOUND? YES NO
B.
I.
2. IF THERE ARE HOLES, DENTS. ETC., WHERE ARE THEY?
C. 1. DOES THE HOOD HAVE A FILTER? YES NO
2. WHEN WAS IT LAST INSPECTED? LAST CHANCED?
III. GENERAL OBSERVATIONS
A. ARE THE VOC EMITTED AT A NOTICEABLE RATE? YES NO
B. ARE THERE CROSS-DRAFTS IN THE ROOM? YES NO
C. IS THE HOOD WELL POSITIONED TO CAPTURE THE VOC? YES NO
D. WHAT IS THE APPROXIMATE DISTANCE FROM THE EMISSION POINT TO
THE IDOD OPENING? FT INCHES
E.
F.
G.
1.
2.
1.
t
1.
2.
3.
DOES THE HOOD APPEAR TO HAVE BEEN MODIFIED OR ALTERED IN
ANY WAY? YES NO
IF YES, HOW?
DOES THE HOOD CAPTURE THE VOC? YES HO
IF HOT, WHAT IS HAPPENING WITH THE VOC?
IS THERE AN ODOR IN THE ROOM? YES
IF SO, WHERE?
NO
IV.
TYPE OF IMSTRUMrST USE!)
B.
C.
WHERE WAS MEASUREMENTS) TAKEN? (DRAW SKETiil BELOW)
INSTRUMENT ?.EAD1HC(S) (IF APPL:O\BL£)
D. OBSERVATIONS
V. SKETCH PROCESS, LOCATION OF HOOD, POSITION OF MEASUREMENT DEVICE
DOES IT SEEM TO BE RELATED TO THE HOOD CAPTURE EFFICIENCY?
YES NO
VI. GENERAL COMMENTS:
B. OBSERVATIONS
-------
TABLE C-2. CHECKLIST FOR INCINERATORS
PLANT _
1. BAOt'Jf.O'JND OATA
INSECT.'?.
DATS
A.
OF INCINLKATfiR: THERMAL
CATALYTIC
II.
B. MINIMUM ALLOWED TtM PLKATURE ON OPERATING ."USMIT
C. OPERATING TEMPERATURE DURING INSPECTION
D. INSTALLATION DATE
A IK SUPPLY FAN
•r
A. HAKE
C. S PEED
E. FAN VIBRATION? YES
B. MODEL NUMBER
D. RATED FLOW RATE
NO
F. MATERIAL BUILDUP ON FAN BLADES? YES
C. FAN BELT (IF USED) LOOSE? YF.S
H. FAN/MOTOR BEARING OVERHEATING? YES
I. BEARING INSPECTION SCHEDULE:
J. BEARING LUBRICATION SCHEDULE:
NO
NO
NO
COULD NOT
CHECK
K. IS HIGH TEMPERATURE GREASE USED? YES
L. COMMENTS:
III. VUC SUPPLY
PER
PER
NO
A. IS DUCTWORK STRUCTURALLY SOUND?
B. IS VOC PREHEATED? YES NO
C. VOC TEMPERATURE: BEFORE PREHEATER
D. VOC PRESSURE: BEFORE PREHEATER
B. 1. FILTER INSTALLED? YES NO
2. FILTER LAST INSPECTED?
AFTER PREHEATER
AFTER PREHEATER
t. 1. VOC BURNER: CLEAN? YES NO
HORN? YES NO
2. VOC BURNER LAST INSPECTED?
LAST CHANGED
COULDN'T
INSPECT
ODULDN1T
INSPECT
V.
C. ADDITIONAL VjC MONITOR ISO ?:VK-.S7 (LIST)
H. COMMENTS
IV. AUXILIARY FUEL
A. TYPE: CAS OIL
B. ivF'. : ".v.'-.iY r?.r.;'t;': .'.•
C. I. FUEL BURNER: CLEAN? YF.S
IF OIL. SULK.'K CONTENT
WORN? YES
2. FUEL BURNER LAST INSPECTED? _
D. FUEL OIL SUPPLY PUMP CONDITION:
E. 1. OIL FILTER: LAST INSPECTED?
r. COMMENTS:
NO
NO
COULDN'T
INSPECT
COULDN'T
INSPECT
LAST REPLACED?
LAST REPLACED?
INCINERATOR CONTROLS
A. LIST EACH PARA.ME.TER THAT IS CONTINUOUSLY MONITORED AND/OR RECORDED
AND ITS READING DURING THE INSPECTION
PARAMETER
READING
B. 1. DOES INCINERATOR HAVE SHUTOFF CONTROLS FOR:
LOW TEMPERATURE? BURNER FLAME-OUT?
FAN SHUTDOWN?
HIGH VOC CONCENTRATION?
2. ARE THESE MANUAL OR AUTOMATIC?
3. ANY ALARMS? YES NO SPECIFY
C. 1. CALIBRATION SCHEDULE FOR CONTROL INSTRUMENTS? YES
2. LAST CALIBRATION OF TEMPERATURE RECORDER?
NO
LAST REPLACED?
3. MAINTENANCE/LUBRICATION SCHEDULE FOR INSTRUMENTS?
4. WHO CONDUCTS THE CALIBRATIONS?
D. COMMENTS:
-------
TABLE C-2 (continued).
VI. RF.FH/.CTOKY
A. I. TYPE OF KEI'&'.-JTORY?
2. THICKNESS OF RF.FIUCTORY:
ItlCIU-'.S
3. IOW OFTEN IS REFRACTORY CIIAiibi .'•?
B. 1. DATE LAiT INSPF.CTi.T
2. INSPECTED BY WSIO.I?
3. ANY PROBLEMS HO TED DURING INSPECTION?
C. NOTICEABLF. 1UT SRITS ON OUTER SUKF.ACE OF OOMflUS riOM CHAMBER?
YES NO
X.
D. NOTICEABLE METAL WAR PACE? YES
E. METAL CONNECTlOI.'S NATE EVENLY? YES
F. COMMENTS:
VII. CATALYST
NO
NO
A. 1. CATALYST MATERIAL?
2. DEPTH OF CATALYST BED?
3. LAST INSPECTION?
INCHES
4. INSPECTED BY WHOM?
5. CONDITION DURING INSPECTION?
6. CATALYST CLEANING SCHEDULE
PER
7. HOW OFTEN IS CATALYST CHECKED FOR POISONING?
8. BY WHOM?
PER
9. DATE OF LAST REPLACEMENT?
10. IS SPARE CATALYST KEPT IN STOCK? YES NO
B. STACK TEMPERATURE MEASUREMENT? YES NO IF YES: *F
C. COMMENTS:
VIII. HEAT EXCHANGERS
A. SUBSTANCE PREHEATED (IDC, COMBUSTION AW, WATER)
B. I. INLET TEMPERATURE *F
C.
2. OUTLET TEMH-RAIUKE
3. STACX TEMP, MATURE _
PHYSICAL INTEGRITY
°f
D. PLANT INSPECTION SCHEDULE
E. COMMENTS:
PER
IX. A. IS INCINERATOR LOCATED OUTSIDE? YES
NO
IS EXTERIOR CORRODED?
RUSTED?
OPERATING LOGS
A. ARE OPERATING LOGS KEPT FOR:
AUXILIARY FUEL USAGE? YES _
INCINERATOR CONTROLS? YES _
CATALYST TEMPERATURES? YES
HEAT EXCHANGERS? YES NO
NO
NO
NO
B. IF POSSIBLE, CHECK OPERATING LOGS FOR SIGNIFICANT DEVIATIONS FOR
SIGNIFICANT DEVIATIONS FROM DESIGN AND NORMAL'OPERATING CDKDTIUNS
XI. SKETCH OF SYSTEM
XII. GENERAL COMMENTS:
-------
PLANT
I. b.VK;;-.-.'ti;n DATA
A. M/.::.TACTURER
B. INSTALLATION
TABLE C-3. CHECKLIST
I:.-1.".:..;-...-
C. HAKF. AMD MODEL K'.V. i!.!l
D. TYPE OF ADSORbKR: rlXED
on:; ti.wr.
FLULDIZED BCD
OTHER (SPECIFY)
E. REASON FOR INSTALLATION OF ADSORBER: TO KELT F-1I.SSICN LIMITS?
TO KEHOVK WXMS?
F. NUMBER OF BEDS
C. BEDS ARE: VERTICAL
HORIZONTAL
H. TYPE OF ADSORBENT: THROWAWAY
KECIINERABLE
ACTIVATED CARBON
OTHER (SPECIFY) _
I. FORM OF ADSORBENT: GRANULAR
_ PELLETIZF.D
J. WHERE IS ADSORBEIIT REGENERATED? ONSITE
POWDER
OFF-SITE (SPECIFY)
K. CAS IMLET STREAM DATA:
DESIGN
FIOW RATE (CFM)
TEMPERATURE ( *F)
RELATIVE HUMIDITY
VOC VAPOR CONCENTRATION
L. NUMBER OF EMISSION POINTS VENTED TO ADSORBER
M. TYPE OF EMISSION POINTS VENTED TO ADSORBER
DURING INSPECTION
N. PERCENT VOC IN SURFACE COATING FORMULATION DURING INSPECTION
FOR ADSORBERS
. O. S'JKFACE COATl.'.'i: APPLICATION :: VPs-. (CAL/iR. L1:/!:.1.!
II.
CHF.tX
III.
IV.
V.
A. ODRROS ION/ASK-AS ION EVIDENT? YES
B. IF YES. IS IT LOCALIZED? YES
C. IF LOCALIZED, SKF.TCH ADSORBER /OJISKOS ION AREAS
VOC FEED
A. VOC CONTENT OF CAS STREAM ENTERING ADSORBER _
B. IS A PREFILTER INSTALLED? YES
C. TYPE OF PREFILTER THROWAWAY FABRIC
D. LAST FILTER INSPECTION:
BLOWER
1C
NO
REPLACEMENT:
HO
A. FAN
1. POSITION OF FAN: ADSORBER INLET
2. IS CORROSION EVIDENT?
3. IS EROSION EVIDENT?
OUTLET
YES
YES
4. IS BUILD-UP ON FAN BLADES EVIDENT? YES
5. IS VIBRATION EVIDENT? YES
INSPECTION SCHEDULE
NO
NO
HO
NO
G.
B: MOTOR
1. EVIDENCE OF OVERHEATED BEARING?
2. INSPECTION SCHEDULE
3. LUBRICATION SCHEDULE
VALVES. DAMPERS
A. ARE ALL VALVES AND DAMPERS LABELED?
YES
PER
PER
YES
NO
B. IF YES. SKETCH LOCATION AND DESIGNATION BELOW
C. IS THERE A STANDARD OPERATING PROCEDURE
(S.O.P.) FOR SWITCHING FROM ONE ADSORBER
BED TO ANOTHER? YES
NO
-------
TABLE C-3 (continued).
D. CAN YOU OBTAIN /. OX'Y OF TliiS S.O.!'. ? y":1.
VI.
A. TYPE OF KECENi'KATLON: STEAM
INERT c/v; (sreciry)
B. REGENERATION STrvKr.M CONTROL DU.'ii1:::
INClNEKiVIOi:
CONDENSER /DF1 CANTER
SECONDARY ADSORBER
OTHER (Si'EClFY)
C. REGENERATION INITIATION METHOD:
I. VAPOR CONCENTRATION
CONCENTRATION LIMIT
LOCATION OF CONCENTRATION
MEASUREMENT DEVICES OUTLKT
MEASUREMENT DEVICES INLET
2. TOED CYCLE
LENGTH OF TIME (HOURS)
ADSORPTION
REGENERATION
DRYING/COOLING
TOTAL CYCLE TIME
3. OTHER (SPECIFY)
D. IF STEAM REGENERATION IS USED:
1. HOW OFTEN ARE STEAM TRAPS BLED?
2. STEAM PRESSURE
VII. WEATHER PROTECTION
A. ADSORBER INSTALLED OUTSIDE?
PPM
MIN
HIM
HIM
MIN
PER
PS I
YES
NO
B. F.LECTRIC IliATEi'. UTILIZES? YES
C. FREEZE UXiniOL TilEWIOSTAT UTILIZCU? YES _
D. OTHER UEAIIER PKOTtCTION MEASURES? (SPECIFY)
VIII. ADSORBENT
IX.
A. 1.
IS ADSOK'F.NT RECULAKLY INSPECTED FOR
DETERIORATION? YES
NO
B.
2.
1.
2.
3.
C. 1.
HDU OFTEN?
IS MAKE-UP ADSORBENT ADDED TO TIIE
BED ON A REGULAR BASIS?
HOW OFTEN?
HOW MUCH IS ADDED?
IS THE ADSORBENT REGULARLY
REPLACED?
PER
YES
NO
PER
YES
NO
2. HOW OFTEN?
ADSORBER INTERNALS
A. ARE THE INTERNALS LINED WITH A PROTECTIVE COATING? YES
B. HOW OFTEN ARE THEY INSPECTED? PER
CLEANED? PER
C. IS THE EXTERIOR WARPED DUE TO EXCESSIVE HEAT? YES
CONDENSED LIQUID
A. IF A CONDENSER/DECANTER IS USED, WHAT
IS DONE WITH NONCONDENSIBLES (I.E., THE
VAPOR EXITING THE CONDENSER /DECANTER)
PER
NO
HO
B. WHAT IS DONE WITH THE CONDENS IBLES?
(I.E., DECANTED LIQUID)?
C. I.
2.
3.
4.
ARE TRANSFER PUMPS INSTALLED?
WHERE ARE THEY LOCATED?
YES
HO
IS THE PUMP SEAL AND/OR THE PACKING
LEAKING? YES
WHEN WAS SEAL AND/OR PACKING LAST
REPLACED?
NO
-------
TABLE C-3 (continued).
is K?\if -,.-.A.IINC ovr.:: ••...•::.•.: •-..••:. 1:0 xin. A. is ADSORBEK USED w SERIES WITH OTIS* OO.STKOL DEVICES?-
WHEN WAS BEARING LAS "I l:^ l-^-.TtS? YES
1J!F.RIC.\T£D? B. WHAT KIND(S)
RLl'LACEU? C. DRAW BELOW THE SEQUENCE OF UNITS
XI. CONTROLS XIV. SKETCH SYSTEM—NOTING IMPORTANT DETAILS
A. DOES FACII.riY HAVE MONITORS A"^/OR R£U)::i-:..;.S
FOR (SFEClrY P. f. AD INC)
PARAMETER «2:iLLl-l:i REOORBilR KKAHING
1. PRESSURE DHUP ACROSS a>;
5. VAPOR OUTLET TEMPERATURE? ( *F)
6. OTHER (SPECIFY)
7. OTHER (SPECIFY)
8. OTHER (SPECIFY)
XII. SAFETY DEVICES INSTALLED
A. FLAME ARRESTOR YES NO
B. RICH BED TEMPERATURE SHUTDOWN YES HO
C. SAFETY RELIEF VALVE YES NO
D. OTHER
E. SAFETY INSPECTION SCHEDULE PER
-------
TABLE C-4. CHECKLIST FOR ABSORBERS
PLANT _
I. SA^XNCl'M) I.'irX-
A. MASUFACTUi:" • ur UNIT
B. INTALLAI iu:.~ u.vrc _
C. RATEU F.FFU'li.KCY _
D. TYPE OF ASSOilllEK: PACKED '-IKn
RATED CAPACIVY
SJL'.TNT UTILI/:I-:D
FILTER MKSH
TRAY
OTHER (SPECIFY)
E. COMPOSITION OF GAS STREAM EUTLl(Ii;C ABSORBER
F. TYPES AND HUMUER OF EMISSION TO I NFS VENTED TO ADSORBER
VEimCAL
C. BED CONFIGURATION:
II. VDC FEED LINE
A. IS IT STRUCTURALLY SOUND?
B. 1. HOLES OR CORROSION OBSERVED?
HORIZONTAL
YES
YES
NO
NO
GLASS
2. IF YES. SKETCH FEED LIKE AND IDLE LOCATION BELOW
C. 1. FILTER INSTALLED ON FEFD LINE? YES _ NO
;. TYPE O/ FILTER
3. INSPECTION SCHEDULE
4. REPLACKy.r.riT SCHEDULE _ _
5. DATE OF LAST REPLACEMENT _
D. FAN
1. PAN ON ABSORBER: INLET? _ OUTLET?
2. VIBRATION EVIDENT? YES NO
PAPER
PER
PER
3. BUILD-UP ON FAN BLADES EVIDENT? YES
4. CORROSION EVIDENT? YES
NO
NO
5. EK'JS !•-•:. EVIDENT? YES
6. AI:E Tii".!<:; 3AMPERS IK 7'~. SYSTEM? Y(-:i
(MA3K TIIEtS IDCU'IU!! v'S EKETiil)
7. FUNCTION OF DANP-..S: EMKKrJHHCY BYPASS
OTHER (SPECIFY)
E. MOTOR
NO
NO
FLCV CONTROL
III.
I. BEARING OVEKKEATED? YES
2. BEARING INSPECTED
3. BEARING LUBRICATED
SOLVENT INLET AND OUTLET LINES
A. SOLVENT RECIRCULATIOH RATE CAL PER _
B. ARE THESE LINES STRUCTURALLY SOUND? YES
C. 1. STRAINER ON INLET LINE? YES
2. STRAINER INSPECTION SCHEDULE
3. STRAINER CLEANING SCHEDULE
D. 1. OUTLET SOLVENT PUMP LEAKING? YES
2. PUMP PACKING AND SEALS INSPECTED? YES
PER
PER
CFM
_ N0
NO
PER
PER
NO
IV.
3. PUMP BEARING OVERHEATING?
4. PUMP BEARING INSPECTED
ABSORBER AIR DISCHARGE LINE
A. MIST ELIMINATOR USED?
B. VDC MONITORING/RECORDING DEVICE
INSTALLED?
YES
_ NO
PER
YES
YES
PER
NO
C. TYPE OF DEVICE (SPECIFY)
D. WC OUTLET CONCENTRATION DURING INSPECTION
-------
TABLE C-4 (continued).
Pii.'.::.: D. IS SOLViM KECLRJJLAriON LIHE BLEU? YES _ NO
A. COLUMN u:v:-:s ;j::s _ FT * _ KT x _ FT IF YES, FREQUENCY: _ PER
B. EXTER10K STKUCTURA'/.Y SOUSJU? VKS _ 1JO __ E. Is SOLVENT STRIPPED (LF.SORBED)? YES _ NO
C. 1. SOi.VJ.-.T SWAY NOZZLES !:..->reCTF.D _ Ptit _ IF YES, HOW? _ PER
2. SOLVENT SPRAY NOZZLES CL-.ANSU _ PER _ VII. SvrTCII OF AdSORBER SYSTEM
3. DATE OF LAST CLEANING __
D. 1. TYPE OF PACKING, FILTEK OK TRAY UTILIZED
2. ABSOKflER PACKING WAY INSPECTED PER
3. ABSORBRK PACKING TRAY CLEANED PER
It. DATE OF LAST CLEANING
E. 1. ABSORBER INTERNALS INSPECTED PER
2. ABSORBER INTERNALS CLEANED PER
M
3. DATE OF LAST CLEANING
F. PRESSURE DROP ACROSS COLUMNS
C. COMMENTS
VI. SOLVENT RECIRCULATIOH LIME
A. STRAINERS AND/OR FILTER INSTALLED? YES NO
B. INDICATE LOCATION OF FILTERS ON SKETCH BELOW
C. I. STRAINERS/FILTERS INSPECTED PER
2. STRAINERS/FILTERS CLEANED PER VIII. GENERAL COMMENTS!
3. DATE OF LAST CLEANING
-------
TABLE C-5. CHECKLIST FOR CONDENSERS
E. 1. WHAT IS TliK AI'MOXLMATr: i:."!i::!T OF TIE V-j-T ^L::E?
1.
A.
is T-U: a\':nE:or.:: lx'> :n u<:ijy
KII.. .•1-.-oT:!C5 r1.".:.1.'; :•..:: CONTROL
YilS
2. IF Vis, WHAT DL'.'l
. 3. SKETCH SECfJENCE OF UMTS -".ELOU
B. TYre OF 00::3ESSER: SURFACE
COI.TACT
OTHER (SPECIFY)
C. COOLANT/KEFS ICERANT USEIJ
II. VOC FEED LINE
A. IS LINE STRUCTURALLY SOUIJU?
B. ARE ALL CONNECTIONS TIGHT AND NONLEAKINC?
C. I. DOES THIS LINE HAVE A FILTER?
2. IF SO, WHAT TYPE: CLASS
YES
YES
YES
PAPER
in
NO
HO
PER
PER
OTHER (SPECIFY)
3. HOW OFTEN IS THE FILTER INSPECTED?
4. HOW OFTEN IS THE FILTER CLEANED?
5. WHEN WAS IT LAST CLEANED?
III. VOC VENT
A. 1. IS A HYDROCARBON ANALYZER INSTALLED
ON THIS VENT? YES NO
2. IF SO, WHO IS THE MANUFACTURER AND WHAT IS MODEL NUMBER?
3. WHAT IS THE CURRENT READING?
4. IS THIS READING KEPT ON A LOG SHEET? YES
5. COMMENTS
NO
IV.
v.
2. OJULH YOU DETKCT AN 0».'?. T-.OH THIS
VEST.'
YcS
3.
VOC D:tAIH MN'i
A. 13 THE LIN1: aTSUCTURALLY SU'JND? YhiS
B. 1. DOES THIS LINE DRAIN INTO A RECOVERY
TANK? YES
2. SKETCH THE POSITION OF TIE CONDENSER
AND THE RECOVERY TANK "iJMW
3. IS THE RECOVERY TANK ABOVE GROUND? YES
4. IF SO, IS IT STRUCTURALLY SOUND WITH
NO SIGNS OF CORROSION AM)
DETER IOKATION? YES
C. 1. WHERE IS THE RECOVERED VOC EVENTUALLY STORED?
2. SKETCH THIS TANK ON THE DIAGRAM BELOW
D. 1. IS A PUMP USED TO TRANSFER THE VOC FROM
THE CONDENSER TO THE RECOVERY TANK? YES
2. FROM THE RECOVERY TANK TO STORAGE? YES
3. DO EITHER OR BOTH OF THESE PUMPS SHOW
SIGNS OF LEAKAGE? YES
E. COMMENTS
REFRIGERATION SYSTEM
A. DO BOTH COOLANT SUPPLY AND RETURN LINES
APPEAR STRUCTURALLY SOUND WITH NO
LEAKAGE OR CORROSION?
YES
B. 1. TYPE OF REFRIGERANT USED
NO
NO
NO
NO
NO
NO
NO
NO
NO
2. REFRIGERANT CHECKED FOR IMPURITIES
3. REFRIGERANT LEVEL CHECKED
4. DATE OF LAST REFRIGERANT ADDITION
AND THE QUANTITY
PER
C. 1. HAS THE REFRIGERATION UNIT HAD ANY
PAST OPERATIONAL PROBLEMS?
YES
NO
-------
TABLE C-5 (continued).
:. i:- bi- - -.\T w-u .'•-••-:;--"•. vii. '_; ^_
3. ii 11 : .j WAS r ..i. ^-i :'-;.!*;. ~
D. i. •.:'-. SPA.SL i >:^ ' : VN .'.'.'Y ;•• . vii:. s;. . • r SYSUM
OF TiL. 'EFRl':i..- .' sV^ri'i: VJS '.V)
2. ir SO. KI!A.- P.V-lTS?
2. WIESE IS TIE V..\1.-K O
IV. OOHOKN5ER
A. ntOPERTIES OF THE INLiT VOC STREAM:
TEMPERATURE *F PRCSSURE
FLOW RATE CFM OIMPOSITION (Z VOCJ
B. WHAT ARE THE INLET (UOLANT PROPERTIES
TEMPERATURE *F PRESSURE
H* C. 1. CAN YOU INSPECT THE PLANT LOGS FOR THE
10 PAST 6 MONTHS FOR OPERATING VALUES? YES NO
2. IF SO. WERE THERE ANY NOTICEABLE
DEVIATIONS? YES NO
3. COMMENTS
D. 1. IS THE EXTERNAL SHELL OF THE
CONDENSER STRUCTURALLY SOUND? YES NO
2. ARE THERE ANY NOTICEABLE LEAKS? YES NO
E. 1. IS THE INTERNAL SURFACE OF THE
CONDENSER REGULARLY INSPECTED? YES NO
2. DATE OF LAST INSPECTION
3. IS IT REGULARLY CLEANED? YES NO
4. DATE OF LAST CLEANING
F. 1. HAS THE CONDENSER HAD A MAJOR
OVKRHAUL FOR ANY REASON? YES NO
2. IF SO, WHY?
3. WHEN WAS THIS WORK DONE?
-------
APPENDIX D
EFFECTS OF CONTROL SYSTEM PROBLEMS
This appendix contains six tables which summarize problems which may
arise with various parts of emission control systems and the effects that
these problems would have on the operation of and the emissions from a control
system.
123
-------
TABLE D-l. EFFECTS OF PROBLEMS WITH HOODS
Effect on:
Problem Operations Emissions
Holes in hood. Possible pressure loss in Fugitive emissions exit
duct. through holes in hood.
Plugged filter in hood. Loss of suction in hood. Emissions escape without
being collected by hood.
Hood poorly positioned None Emissions escape without
to capture emissions. being collected by hood.
124
-------
TA1JLE D-2. EFFECTS OF PROBLEMS WITH DUCTWORK
Effect on:
1'rohlem
Operation.-;
Emissions
Corroded, eroded metal
ductwork.
Pressure loss in duct.
Ductwork is vunerable
to l»einft hit by moving
vehicles.
Moving vehicle may damage
ductwork, create holes.
Pollutant stream diluted
with ambient air;
decreased capture effi-
ciency resulting in
increased emissions.
Fugitive emissions from
holes in ducts.
Uui ldu|> ol resinous
materials inside duct.
Dampers not properly
labeled (e.^., open,
close).
Possible reduction in flow
area or fire if material
is combustible.
Operator may confuse
damper settings.
Possible damage to duct
resulting in fugitive
emissions.
Imbalance of airflow
in ductwork network
reduces capture effi-
ciency at certain hoods
and results in increased
emissions.
Dampers open at
improper time.
None
Room air from unused
coating operation dilutes
VOC stream, reducing
capture efficiency and
resulting in increased
emissions.
125
-------
TABLIi l)-3. EFFECTS OF PROBLKMS WITH FANS
Profiler.
Effect on:
Operations
Emissions
Fan motor, bearing
over hfi.it ing.
Fan imbalance.
Spare parts (bearing,
b<:lt) not k«pt in
stock.
Reduced fan efficiency, Emissions escape at
suction and VOC capture at source without being
hoods. collected.
Reduced fan efficiency, Emissions escape at
suction and VOC capture at source without being
hoods. collected.
System down until spare
part can he obtained.
Facility will most likely
vent emissions to atmos-
phere while control system
is down.
Belt is slipping,
broken.
Hamper at fan is not
open wide enough.
Fan will not turn at rated Emissions escape at source
rpm. without being collected.
Excessive pressure drop
across fan leading to
overheating of motor.
Emission escape due to
reduced suction.
126
-------
TAHLE D-4. EFFECTS OF PROBLEMS WITH INCINERATOR UNITS
Problem
Effect on:
Operations
Emissions
Ope rat i ng temperature
lower than stated on
permit.
Fan malfunction.
Vapor stream not
prehc.ited.
Reduced VOC combustion
efficiency.
Loss of VOC; excess airflow
to incinerator.
Additional heat required
to raise vapor stream to
combustion temperature.
Burners plugged, worn. Flame out.
Incinerator controls
not calibrated.
Incinerator has no
controls.
Improper refractory for
high temperatures.
Fuel filter plugged.
Catalyst plugged,
poisoned.
Catalyst not cleaned,
replaced on regular
schedule.
Low temperature, high VOC
concentration, fan failure.
Low temperature, high VOC
concentration, fan failure.
Warping, deformation of
metal shell.
Decreased auxiliary fuel
flow.
Inefficient adsorption of
VOC on catalyst surface.
Inefficient adsorption of
VOC on catalyst surface.
VOC pass through
incinerator without being
completely oxidized.
Incomplete combustion of
VOC resulting in emissions
higher than design level.
Incomplete combustion.
VOC are not combusted.
VOC not completely
combusted.
VOC not completely
combusted.
Fugitive emissions leaking
from incinerator unit.
Incomplete combustion of
VOC's.
Incomplete combustion of
VOC.
Incomplete combustion of
VOC.
Heat exchanger fouled,
leaking.
Insufficient preheat of
VOC vapor to incinerator.
Excess emissions due to
incomplete combustion.
VOC may bypass incinerator
through leaks.
127
-------
TABLE D-5. EFFECTS OF PROBLEMS WITH ADSORPTION UNITS
Problem
Effect on:
Operations
Emissions
Gradual loss of
adsorbent due to
entrainment.
Loss of adsorption capa-
city, premature saturation
of bed.
Kegenuration concentra- Regeneration will be
tion detector/initiator initiated improperly.
poorly calibrated.
VOC inlet vapor concen- Adsorbent is prematurely
tration higher than saturated. Also, possible
design value. hot spots and bed fires
may occur.
Emergency bypass damper Loss of vapor stream to
opened. adsorber.
Regeneration steam
traps not hied.
Steam becomes saturated
(wet).
Breakthrough (emission
of uncaptured VOC) occurs
much sooner.
Possible premature break-
through.
Premature breakthrough.
Emissions bypass control
unit and are vented to
atmsophere.
Bed is saturated with
water and cannot adsorb
VOC.
Adsorbent not inspected,
replaced on regular
schedule.
Internal vessel liner
chipped, abraded.
Plugged prefilter.
Blower (fun) f.ail.urc
(e.g., bearings, belt,
motor).
Buildup of particulates,
nonregenerable organics
on adsorbent may occur.
Eventual corrosion,
erosion of vessel walls.
Exessive pressure drop in
vapor line.
Reduced flow to adsorber.
Premature breakthrough.
Fugitive emissions exit
through vessel walls.
Increase in bed exhaust
concentrations.
Increase in bed exhaust
concentrations.
Inlet vapor stream
relative humidity >5U%.
Noure^enerable compounds
present in inlet vapor
stream.
Water vapor competes with
VOC for adsorption sites.
Bed fouling, less adsorp-
tion capacity.
Breakthrough occurs
much sooner.
Breakthrough occurs
much sooner.
(continued)
128
-------
TABLE D-5 (continued)
Effect on:
Problem
Operations
Emissions
Corrosion in adsorber. Pressure loss in bed.
V.-jpor stream inlet Kevaporization of low
temperature higher than boiling compounds will
design value. occur.
Inlet vapor stream Potential excess heat
relative humidity <20%. buildup in bed.
Highly exothermic Hot spots, bed fires may
solvents (e.g., ketones, occur resulting in adsorp-
phenols) present in tion capacity loss.
inlet vapor stream.
Comlensibles transfer
pump Leaking.
Control system poorly
maintained.
Leaking condensed
organics.
Poorly controlled system.
Fugitive emissions from
adsorber vessel.
Exhaust VOC concentra-
tions higher than design
value.
Breakthrough occurs much
sooner.
Exhaust VOC concentrations
in excess of emission
limits.
Vaporization of leaked
organics.
Potential excess concen-
trations of VOC in
adsorber exhaust stream.
129
-------
TABLE D-6. EFFECTS OF PROBLEMS WITH ABSORi'TlON UNITS
Problem
Effect on:
Operations
Emissions
Incorrect solvent used
in absorber (e.g.,
water used to absorb
VOC).
Plugged prefilter on
vapor inlet.
Incomplete absorption of
immiscible vapor.
Excess pressure drop in
vapor inlet line.
VOC pass through bed with
negligible control.
Possible increase in
exhaust VOC concentra-
tions.
Fan fai lure.
Plugged solvent
reelreulation line
strainer.
Solvent recirculation
pump leaking or over-
heating.
bypass damper open.
Solvent, spray nozzles
Packing trap plugged or
fouled.
Stripping column
temporalure too low.
Solvent recirculation
line not bled
frequently enough.
Reduced vapor flow through
vessel, poor gas/liquid
contact.
Reduced liquid flow to
absorber.
Reduced liquid flow to
absorber.
Vapor stream bypasses
absorber.
Poor solvent distribution
in absorber.
Excess pressure drop
through vessel, poor gas/
liquid contact.
Absorbed VOC not fully
desorbed from solvent.
Buildup of VOC in solvent
results in reduced solvent
absorption capacity.
Exhaust VOC concentra-
tion exceeds design limit.
Exhaust VOC concentration
exceeds design limit.
Exhaust VOC concentration
exceeds design limit.
VOC vented directly to
atmosphere.
Exhaust VOC concentration
exceeds design limit.
Exhaust VOC concentration
exceeds design limit.
Exhaust VOC concentration
exceeds design limit.
Exhaust VOC concentration
exceeds design limit.
130
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